Bivalent mRNA booster encoding virus-like particles elicits potent polyclass receptor-binding domain antibodies in pre-vaccinated mice

mRNA vaccines emerged as a leading platform for the rapid and scalable development of effective vaccines during the COVID-19 pandemic (Corbett et al., 2020). Currently approved mRNA vaccines encode the SARS-CoV-2 spike (S) trimer (Zheng et al., 2022), the main target for neutralizing antibodies (Abs) produced during natural infection (Chen et al., 2023). S-encoding mRNAs formulated in lipid nanoparticles (LNPs) are taken up by cells, which promotes translation and cell surface expression of S trimers to activate B cells (Hogan and Pardi, 2022). Translation of mRNA-encoded S protein within host cells also provides viral peptides for presentation on MHC class I molecules, which are recognized by cytotoxic T cells (Painter et al., 2021; Oberhardt et al., 2021).

Initial two-shot COVID-19 mRNA vaccination series became available in December 2020 after clinical studies demonstrated protection from severe disease after SARS-CoV-2 infection (Polack et al., 2020; Baden et al., 2021). However, the durability of mRNA vaccine-induced immune protection was limited by two factors. First, serum Ab levels contracted over several months (Zhang et al., 2022). Second, SARS-CoV-2 variants acquired mutations in the S protein, which reduced their sensitivity to vaccine-induced neutralizing Abs (Planas et al., 2021). As a result, a third dose of the original mRNA vaccine encoding the ancestral Wuhan-Hu-1 (Wu1) S protein was offered starting in fall 2021 (Andrews et al., 2022b).

The emergence of the Omicron BA.1 variant in November 2021 (WHO, 2021) sparked concern because of its levels of substitution in S, especially in the receptor-binding domain (RBD), resulting in effective evasion of Ab-mediated immunity (Liu et al., 2022; Cele et al., 2022) and increased rates of symptomatic infections in previously vaccinated individuals (Andrews et al., 2022a; Tseng et al., 2022). Although undetectable after the initial mRNA vaccine series, a third dose of the original mRNA vaccine elicited neutralizing Abs against BA.1, but BA.1 neutralizing titers were lower compared to titers against the ancestral Wu1 variant (Gruell et al., 2022). The subsequent emergence of Omicron subvariants such as BA.5, BQ.1.1, and XBB.1, which exhibited progressively reduced sensitivities to vaccine-induced neutralizing Abs (Wang et al., 2023c), prompted the development of bivalent mRNA boosters, which included mRNAs encoding both the Wu1 and the BA.5 S proteins (Scheaffer et al., 2023). Preclinical and clinical studies found that bivalent boosters elicited modestly improved neutralizing Ab responses against Omicron subvariants compared to a fourth dose of the original monovalent vaccine (Scheaffer et al., 2023; Khoury et al., 2023; Chalkias et al., 2022; Collier et al., 2023; Davis-Gardner et al., 2023), although some studies found no differences between monovalent and bivalent boosters following initial vaccination with the original Wu1 S-encoding mRNA vaccine (Wang et al., 2023a; Wang et al., 2023b). Several studies (Chalkias et al., 2022; Collier et al., 2023; Wang et al., 2023b; Alsoussi et al., 2023; Park et al., 2022; Carreño et al., 2023) showed that the effectiveness of bivalent boosters was limited by immune imprinting, which occurs when prior exposure to an antigen shapes immunological responses to related antigens during subsequent exposures (Cobey and Hensley, 2017). Instead of generating de novo Omicron-specific immune responses, bivalent boosters primarily activated pre-existing cross-reactive memory B cells from previous vaccinations and/or infections (Alsoussi et al., 2023; Park et al., 2022; Carreño et al., 2023), leading to lower neutralizing activity against Omicron subvariants compared to the ancestral variant (Chalkias et al., 2022; Collier et al., 2023; Wang et al., 2023b).

Continued development of updated boosters in response to emerging variants was slowed by the need for additional clinical testing, regulatory approvals, and adjustments to the manufacturing process. As a result, bivalent boosters became available in fall 2022, almost 1 year after the emergence of Omicron (Song et al., 2024). These challenges highlight the urgent need for innovative vaccine strategies that achieve more lasting immune protection against rapidly evolving viruses such as SARS-CoV-2, thereby reducing the need for frequent and updated boosters.

We recently developed the ESCRT- and ALIX-binding region (EABR) mRNA vaccine platform that combines features of mRNA and protein nanoparticle (NP) vaccines through delivery of mRNA-encoded self-assembling enveloped virus-like particles (eVLPs) (Hoffmann et al., 2023). eVLP assembly is achieved by fusing a short EABR sequence to the cytoplasmic tail of viral surface proteins, which recruits proteins from the Endosomal Sorting Complex Required for Transport (ESCRT) pathway. Thus, EABR mRNA vaccines promote dual presentation of S trimers on cell surfaces and eVLPs that bud from the plasma membrane. Immunizations in mice showed that an EABR mRNA vaccine encoding a Wu1 SARS-CoV-2 S elicited superior neutralizing Ab potency and breadth against ancestral and Omicron SARS-CoV-2 variants compared to conventional mRNA and protein NP vaccines (Hoffmann et al., 2023). Similar to conventional mRNA vaccines, the EABR mRNA vaccine also induced potent T cell responses, consistent with the presence of S-specific cytotoxic T cells (Hoffmann et al., 2023). These findings suggest that the EABR mRNA vaccine approach has the potential to enhance monovalent or bivalent booster-induced Ab responses against Omicron subvariants in the context of pre-existing immunity induced by prior vaccination, infection, or both.

Here, we evaluated the ability of EABR mRNA boost immunogens to elicit potent and broad humoral immune responses against SARS-CoV-2 variants in pre-vaccinated mice. We demonstrate that the EABR mRNA vaccine approach improves monovalent and bivalent booster-mediated neutralizing Ab responses against Omicron subvariants compared to conventional mRNA boosters. Epitope mapping of polyclonal antisera further showed that a bivalent EABR mRNA booster elicited a more diversified anti-RBD IgG response than other tested boosting immunogens. These findings support the use of the EABR mRNA vaccine platform for the design of effective boosters that could confer more lasting protection against SARS-CoV-2 variants and potentially other rapidly evolving viruses. In addition, our work provides structural evidence that bivalent mRNA immunizations promote heterotrimer formation, which could enhance activation of cross-reactive B cells through intra-S crosslinking. These insights inform the future design of bivalent or multivalent COVID-19 boosters and highlight the need for further investigation into potentially beneficial effects of S heterotrimer formation on vaccine-induced immune responses against trimeric viral Ss.

To expand upon our previous characterizations of a monovalent SARS-CoV-2 S-EABR mRNA vaccine (Hoffmann et al., 2023), we evaluated the potential of the EABR mRNA vaccine approach for monovalent and bivalent SARS-CoV-2 immunizations in pre-vaccinated mice. Four cohorts of 10 BALB/c mice each initially received prime-boost intramuscular (IM) vaccinations on days 0 and 28 with 2 µg of a conventional mRNA vaccine encoding the ancestral S protein from the Wu1 variant, similar to the immunogens used in initially approved COVID-19 mRNA vaccines (Wu1 S mRNA-LNP) (Figure 1A–C). To simulate the timing of the third available COVID-19 mRNA vaccine dose in humans, booster immunizations were administered on day 230, nearly 7 months after the primary vaccination series, with each cohort receiving a different boost immunogen (Figure 1A–C). Consistent with the COVID-19 booster that became available in fall 2021 (Andrews et al., 2022b), cohort 1 received a third dose of 2 µg Wu1 S mRNA-LNP (Figure 1B and C). To evaluate whether formation of mRNA-encoded S-EABR eVLPs enhances booster immunogenicity in pre-vaccinated mice, cohort 2 received 2 µg Wu1 S-EABR mRNA-LNP (Figure 1B and C). Cohort 3 received a bivalent Wu1/BA.5 S mRNA-LNP booster (1 µg Wu1 S mRNA-LNP combined with 1 µg BA.5 S mRNA-LNP), which resembled the COVID-19 booster that became available in fall 2022 (Song et al., 2024; Figure 1B and C). Lastly, cohort 4 received a bivalent Wu1/BA.5 S-EABR mRNA-LNP booster (1 µg Wu1 S-EABR mRNA-LNP combined with 1 µg BA.5 S-EABR mRNA-LNP) to promote the formation of eVLPs that co-display Wu1 and BA.5 S trimers (Figure 1B and C). The Wu1 and BA.5 S-EABR constructs were designed as previously described by fusing an endocytosis-preventing motif (EPM), a short Gly-Ser linker, and an EABR sequence to the end of the cytoplasmic domain of Wu1 and BA.5 S trimers (Hoffmann et al., 2023; Figure 1—figure supplement 1A). The Wu1 and BA.5 S-EABR constructs induced similar levels of eVLP budding in transiently transfected HEK293T cells (Figure 1—figure supplement 1B).

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Serum binding Ab responses were measured by enzyme-linked immunosorbent assay (ELISA) 4 and 18 weeks after the primary vaccination series (days 56 and 154) and 2 weeks after the booster immunizations (day 244). As previously observed, the initial Wu1 S mRNA-LNP vaccinations elicited high binding Ab titers against soluble Wu1 S-6P trimers (contain 6 proline substitutions to enhance expression and stability) (Hsieh et al., 2020), and as expected, these titers were similar for all cohorts on day 56 (Figure 1D). Robust binding Ab responses were also detected for all cohorts against Omicron BA.5, BQ.1.1, and XBB.1 S-6P trimers on day 56 (Figure 1E–G). On day 154, binding Ab levels against all variants dropped slightly, which was consistent between cohorts (Figure 1D–G). On day 244, all boost immunogens increased binding Ab titers against Wu1, BA.5, BQ.1.1, and XBB.1 S-6P trimers compared to titers measured on days 56 and 154, but no differences were observed between cohorts for all time points (Figure 1D–G).

Bivalent S-EABR mRNA-LNP booster elicits potent Ab responses targeting Omicron RBDs

We next evaluated the impact of the different boost immunizations on Ab responses against the RBD, the primary target of neutralizing Abs (Chen et al., 2023). The initial Wu1 S mRNA-LNP prime-boost vaccinations elicited robust and similar Ab responses against the Wu1 RBD for all cohorts on day 56 (Figure 2A). The BA.5, BQ.1.1, and XBB.1 variants harbor multiple RBD substitutions, particularly within the class 1 and 2 epitopes at the tip of the RBD (Barnes et al., 2020; Figure 1—figure supplement 2), promoting effective escape from neutralizing Abs (Wang et al., 2023c). Compared to Wu1 RBD binding, Ab binding titers were weaker against the BA.5, BQ.1.1, and XBB.1 RBDs on day 56 (Figure 2B–D). The robust Ab binding against the BA.5, BQ.1.1, and XBB.1 S trimers (Figure 1E–G) in the absence of strong RBD responses was at least in part driven by potent responses against the S2 stem region of S (residues 686–1213) (Figure 1—figure supplement 3), which is relatively conserved in SARS-CoV-2 variants (Li and Chang, 2023; Figure 1—figure supplement 2). Similar to binding titers against S-6P trimers (Figure 1D–G), Wu1, BA.5, BQ.1.1, and XBB.1 RBD binding slightly dropped on day 154 without statistically significant differences between cohorts (Figure 2A–D). The booster immunizations increased Wu1 RBD binding on day 244 compared to day 56 and 154 levels, but no differences were detected between the four boosting immunogens (Figure 2A). In contrast, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster elicited the highest BA.5, BQ.1.1, and XBB.1 RBD responses on day 244 (Figure 2B–D), which were significantly higher than Wu1 S mRNA-LNP booster-induced responses against BQ.1.1 RBD (p=0.0499) (Figure 2C) and narrowly failed to reach statistical significance compared to Wu1 S mRNA-LNP booster-induced responses against BA.5 RBD (p=0.07) (Figure 2B). Compared to baseline titers measured prior to boost immunizations on day 154, the bivalent Wu1/BA.5 S-EABR mRNA-LNP immunization elicited significantly larger increases in BA.5 RBD binding than the monovalent Wu1 S mRNA-LNP (p=0.02) and the bivalent Wu1/BA.5 S mRNA-LNP boosters (p=0.01) (Figure 2B), as well as significantly larger increases in BQ.1.1 RBD binding than the Wu1 S mRNA-LNP booster (p=0.002) (Figure 2C). While overall titers were similar on day 244, the monovalent Wu1 S-EABR mRNA-LNP booster consistently induced larger increases in Ab binding to the BA.5, BQ.1.1, and XBB.1 RBDs than the monovalent Wu1 S mRNA-LNP booster (Figure 2B–D), although these differences failed to reach statistical significance. The monovalent Wu1 and bivalent Wu1/BA.5 S mRNA-LNP boosters elicited similar binding titers against the BA.5 and XBB.1 RBDs (Figure 2B and D), but the bivalent booster induced slightly higher responses and a larger increase compared to day 154 titers against BQ.1.1 RBD (not statistically significant) (Figure 2C). Overall, these results demonstrate that booster immunizations with the bivalent Wu1/BA.5 S-EABR mRNA-LNP elicited the highest Ab responses against Omicron RBDs in pre-vaccinated mice. Notably, post-boost Ab binding against Omicron RBDs remained lower than binding titers against Wu1 RBD in all cohorts, suggesting that booster responses were affected by immune imprinting induced by the primary vaccination series.

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Bivalent S-EABR mRNA-LNP booster elicits higher neutralizing responses against Omicron variants

The ability of boost immunogens to elicit neutralizing Ab responses in pre-vaccinated mice was evaluated by in vitro pseudovirus neutralization assays (Crawford et al., 2020; Robbiani et al., 2020). The primary vaccination series with Wu1 S mRNA-LNP elicited potent and consistent autologous geometric mean neutralizing titers as assessed by half-maximal serum inhibitory dilution (ID₅₀) values against Wu1 pseudovirus in all cohorts on day 56 (Figure 3A; Supplementary file 1). Neutralizing activity was >100-fold lower against the BA.5 variant and undetectable in most animals against the BQ.1.1 and XBB.1 variants on day 56 for all cohorts (Figure 3B–D; Supplementary file 1). On day 154, neutralizing titers against the Wu1 and BA.5 variants were consistent in all cohorts and slightly lower compared to day 56 titers (Figure 3A and B; Supplementary file 1). Neutralizing activity against the BQ.1.1 and XBB.1 variants was undetectable in all but one animal on day 154 (Figure 3C and D; Supplementary file 1). Booster immunizations on day 230 increased autologous neutralizing titers against Wu1 pseudovirus on day 244 compared to day 154 in all cohorts (Figure 3A; Supplementary file 1). Monovalent Wu1 S mRNA-LNP and S-EABR mRNA-LNP immunizations elicited the smallest and largest increases in Wu1 neutralization (4.2-fold versus 6.6-fold), respectively. All boost immunogens elicited increased BA.5 neutralizing activity on day 244 compared to day 56 and 154 titers (Figure 3B; Supplementary file 1). Boosting with monovalent Wu1 S-EABR mRNA-LNP induced 4.8-fold higher BA.5 neutralizing titers than a third Wu1 S mRNA-LNP immunization, but this difference did not reach statistical significance. Using the respective day 154 titers as baseline, the Wu1 S-EABR mRNA-LNP booster induced a 23.8-fold increase in BA.5 neutralization on day 244 compared to only a 6.3-fold increase detected after boosting with Wu1 S mRNA-LNP (not statistically significant) (Figure 3B; Supplementary file 1). Compared to day 56 baseline titers, the Wu1 S-EABR mRNA-LNP booster induced a significantly higher increase in BA.5 neutralization on day 244 than the conventional Wu1 S mRNA-LNP booster (16.2-fold versus 3.1-fold; p=0.048) (Figure 3—figure supplement 1; Supplementary file 1). The Wu1 S-EABR mRNA-LNP booster also elicited 3.4-fold higher neutralizing responses than the Wu1 S mRNA-LNP booster against the Omicron BA.1 variant on day 244 (p=0.03) (Figure 3—figure supplement 2). Based on day 154 titers, boosting with monovalent Wu1 S-EABR mRNA-LNP induced significantly higher increases in BA.1 neutralization compared to monovalent Wu1 S mRNA-LNP (8.8-fold versus 2.5-fold; p=0.009) (Figure 3—figure supplement 2). Interestingly, the monovalent Wu1 S-EABR mRNA-LNP and the bivalent Wu1/BA.5 S mRNA-LNP boosters elicited similar BA.5 neutralizing responses on day 244 (Figure 3B; Supplementary file 1), suggesting that the EABR mRNA vaccine approach might reduce the need for updating boost immunogens to achieve robust Ab responses against emerging SARS-CoV-2 variants. The highest BA.5 neutralizing titers were elicited by the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster, which were 12.3-fold higher than titers induced by the monovalent Wu1 S mRNA-LNP booster (p=0.02) and 2.4-fold higher than titers induced by the bivalent Wu1/BA.5 S mRNA-LNP booster (not statistically significant). Based on titers measured on day 154, the Wu1/BA.5 S-EABR mRNA-LNP booster induced a 67-fold increase in BA.5 neutralization, which was significantly higher than the increase elicited by boosting with monovalent Wu1 S mRNA-LNP (p=0.003).

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While the BA.5 neutralizing activity induced by the monovalent Wu1 S and S-EABR mRNA-LNP boosters can likely be attributed to cross-neutralizing Abs that neutralize both the Wu1 and BA.5 variants, it is possible that the bivalent Wu1/BA.5 S and S-EABR mRNA-LNP boosters also elicited de novo strain-specific Abs that neutralize BA.5 but not Wu1. Day 244 serum samples from mice that received bivalent Wu1/BA.5 S or S-EABR mRNA-LNP boosters were depleted of Abs that bind to Wu1 RBD. Sera were passaged over a column presenting either a mock protein (HIV-1 gp120) as a control or the Wu1 RBD to remove cross-neutralizing anti-RBD Abs while retaining BA.5 RBD-specific Abs. Following depletions, residual neutralization activity was measured against the BA.5 variant. Interestingly, Wu1 RBD depletion resulted in 17- and 36-fold lower geometric mean neutralizing titers compared to mock depletion for the bivalent Wu1/BA.5 S and S-EABR mRNA-LNP boosters, respectively (Figure 3—figure supplement 3). In both cohorts, BA.5 neutralizing titers in all but two mice dropped below ID₅₀ values of 1:120 following Wu1 RBD depletion, consistent with the neutralizing activity in these samples being primarily driven by cross-neutralizing Abs targeting the RBD induced by the primary vaccination series. The potent residual neutralizing activity observed in two mice in each cohort after Wu1 RBD depletion implies either the presence of boost-induced de novo BA.5-specific RBD Abs or neutralizing non-RBD Abs that target another region of S, e.g., the N-terminal domain (Wang et al., 2022) or S2 (Li and Chang, 2023).

Booster immunizations had less pronounced effects on neutralization activity against the BQ.1.1 and XBB.1 variants. Against BQ.1.1 pseudovirus, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster elicited the most potent neutralizing activity on day 244, which was significantly higher than responses induced by a third immunization with the monovalent Wu1 S mRNA-LNP booster (p=0.0495) (Figure 3C; Supplementary file 1). The monovalent Wu1 S-EABR mRNA-LNP and bivalent Wu1/BA.5 S mRNA-LNP boosters elicited 1.8- and 2.5-fold higher BQ.1.1 titers than the monovalent Wu1 S mRNA-LNP booster, respectively, the latter of which narrowly failed to reach statistical significance (p=0.07). Based on day 154 BQ.1.1 neutralizing titers, the monovalent Wu1 S mRNA-LNP and bivalent Wu1/BA.5 S-EABR mRNA-LNP boosters induced the smallest and largest increases in neutralizing activity on day 244, respectively (1.4-fold versus 4.7-fold; p=0.0495). The monovalent Wu1 S-EABR mRNA-LNP and bivalent Wu1/BA.5 S mRNA-LNP boosters elicited 2.4- and 3.4-fold increases in neutralizing BQ.1.1 titers, respectively. Notably, day 244 neutralizing titers against BQ.1.1 were substantially lower than BA.5 neutralizing titers for all boost immunogens (Figure 3B and C; Supplementary file 1), consistent with previous reports (Wang et al., 2023c; Miller et al., 2023). Notably, Ab binding responses against the BA.5 and BQ.1.1 RBDs were similar (Figure 2B and C), implying that RBD binding responses are not always predictive of neutralizing activity against Omicron subvariants.

Neutralizing responses against the XBB.1 variant were slightly lower than titers against BQ.1.1 pseudovirus (Figure 3D; Supplementary file 1). Once again, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster elicited the highest XBB.1 neutralizing titers, which were 2.1-fold higher than titers induced by the monovalent Wu1 S mRNA-LNP booster (not statistically significant). Based on day 154 titers, the monovalent Wu1 and bivalent Wu1/BA.5 S-EABR mRNA-LNP boosters increased XBB.1 neutralization by 2.5- and 3.2-fold, respectively, while conventional monovalent and bivalent S mRNA-LNP boosters only induced 1.5- and 2.2-fold increases, respectively.

Notable differences were also observed in the number of mice in each cohort that reached robust neutralizing titers (defined as ID₅₀s exceeding 1:100) against Omicron subvariants following booster immunizations, titers that are likely important for the prevention of symptomatic infections (Feng et al., 2021). The primary vaccination series with Wu1 S mRNA-LNP elicited robust neutralizing titers against the Wu1 variant in all mice on day 56 (Figure 3E). However, the initial Wu1 S mRNA-LNP vaccinations elicited robust titers in only 6–8, 1–3, and 0–2 of 10 mice against the BA.5, BQ.1.1, and XBB.1 variants on day 56, respectively. On day 154, ID₅₀s over 1:100 were measured for 3–5 mice in each cohort against BA.5, but for none of the animals against BQ.1.1 and XBB.1. While a third immunization with Wu1 S mRNA-LNP induced robust titers against BA.5 in only 8 of 10 mice on day 244, the monovalent Wu1 S-EABR mRNA-LNP booster induced robust titers against BA.5 in all 10 mice, including the 4 mice that did not have detectable BA.5 neutralizing activity on day 56 (Figure 3E). As expected, robust neutralizing titers against the BA.5 variant were also observed in all mice that received the bivalent Wu1/BA.5 S or S-EABR mRNA-LNP boosters. Against the BQ.1.1 and XBB.1 variants, a third immunization with Wu1 S mRNA-LNP induced robust neutralizing titers in only 2 and 3 mice, respectively (Figure 3E). In comparison, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster induced ID₅₀s over 1:100 in 7 and 6 mice against the BQ.1.1 and XBB.1 variants, respectively.

Overall, these results demonstrate that the EABR mRNA vaccine approach improves the neutralizing activity against Omicron subvariants induced by monovalent and bivalent boost immunogens in pre-vaccinated mice.

Bivalent S-EABR mRNA-LNP booster induces polyclass Ab responses

Several distinct Ab-binding epitopes have been defined on RBDs, including the variable class 1 and 2 RBD epitopes and the more conserved class 3, 4, 1/4, and 5 RBD epitopes (Barnes et al., 2020; Fan et al., 2022; Fan et al., 2025; Figure 1—figure supplement 2). We determined which RBD epitopes were targeted by booster-induced Abs in pre-vaccinated mice using deep mutational scanning (DMS) of yeast display libraries derived from Wu1 (Starr et al., 2020) and XBB.1.5 RBDs (Taylor and Starr, 2023). In previous studies, we showed that equimolar mixtures of monoclonal Abs targeting distinct RBD epitopes produced less pronounced DMS escape peaks, which we defined as a polyclass Ab response (Cohen et al., 2024). This suggests that polyclonal serum that includes roughly equal distributions of Abs targeting multiple classes of RBD epitopes would exhibit relatively flat DMS profiles, while more defined DMS escape peaks would be observed for less diverse polyclonal serum responses containing Abs that primarily target particular RBD epitopes (Cohen et al., 2024). For this study, we used DMS escape fractions to define polyclass responses. Escape fractions for each RBD mutation range from 0 (no cells with this mutation are sorted into the serum Ab escape bin) to 1 (all cells with this mutation are sorted into the serum Ab escape bin) (Greaney et al., 2021b). Total escape peaks represent the sum of escape fractions for all mutations at a specific site (Greaney et al., 2021b). DMS profiles with total escape peaks below 0.5 at all sites were classified as polyclass responses. In contrast, DMS profiles with total escape peaks of 0.5–1, 1–2, or above 2 at one or more sites were classified as weak, moderate, or strong escape profiles, respectively, indicating weak, moderate, or strong targeting of particular RBD epitopes (Supplementary file 2). DMS was performed for 6 serum samples for each cohort, which were selected based on XBB.1 neutralization activity (1st, 2nd, 3rd, 5th, 6th, and 10th best neutralizer from each cohort). For the Wu1 RBD library, only 5 DMS profiles were obtained due to poor sequencing quality for one sample in each cohort.

Against the Wu1 RBD library, immunizations with the monovalent Wu1 S and S-EABR mRNA-LNP boosters or the bivalent Wu1/BA.5 S mRNA-LNP booster resulted in DMS profiles consistent with moderate targeting of the variable class 2 epitope primarily inducing escape at RBD residue 484 (Figure 4A and B). The bivalent Wu1/BA.5 S mRNA-LNP booster also elicited weak to moderate responses that mapped to the variable class 1 and class 3 RBD epitopes. In contrast, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster DMS profiles were consistent with polyclass Ab induction, suggesting a more diverse response targeting multiple RBD epitopes (Figure 4A and B). Notably, samples from 4 out of 5 mice in this cohort exhibited polyclass DMS profiles, whereas moderate to strong escape fractions for class 1, 2, or 3 epitopes were observed in 3–4 mice in each of the other cohorts (Figure 4—figure supplement 1; Supplementary file 2).

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As expected, no class 1 and 2 DMS profiles were observed against the XBB.1.5 RBD library (Taylor and Starr, 2023) since these epitopes are highly substituted in Omicron subvariants (Figure 1—figure supplement 2). All booster immunizations induced strong class 5 escape peaks targeting RBD residues 352, 357, 396, and 468 (Figure 4C and D). Importantly, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster induced a less pronounced overall class 5 profile than the other boost immunogens, which was primarily driven by a strong class 5 response observed in a single animal in this cohort (Figure 4—figure supplement 2; Supplementary file 2). The other mice that received the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster exhibited polyclass or weak to moderate responses against class 4 and 5 epitopes. In contrast, strong class 5 profiles were detected in 4–5 mice in cohorts that received the monovalent Wu1 S or S-EABR mRNA-LNP boosters or the bivalent Wu1/BA.5 S mRNA-LNP booster (Figure 4—figure supplement 2; Supplementary file 2). Overall, these results suggest that the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster induced a more diversified polyclass Ab response that likely contributed to the higher neutralizing activity observed against Omicron subvariants, which could result in more effective recognition of future variants.

Co-expression of Wu1 and BA.5 S results in heterotrimer formation

The results from this and previous studies Scheaffer et al., 2023; Khoury et al., 2023; Chalkias et al., 2022; Collier et al., 2023 demonstrated that bivalent booster immunizations improve the potency and breadth of Ab responses against Omicron subvariants compared to monovalent boosters. Serum depletion assays also showed that the BA.5 neutralizing activity elicited by the bivalent Wu1/BA.5 S and S-EABR mRNA-LNP boosters was primarily driven by cross-reactive Abs that bind to the Wu1 and BA.5 RBDs (Figure 3—figure supplement 3). Preferential activation of cross-reactive B cells could be achieved through co-display of Wu1 and BA.5 S trimers on the surface of a cell and/or an eVLP (Figure 1C), which could result in inter-S crosslinking between cross-reactive B cell receptors (BCRs) and neighboring homotrimeric Wu1 and BA.5 S trimers (Figure 5—figure supplement 1). As an additional mechanism for bivalent booster-induced activation of cross-reactive B cells, we hypothesized that co-expression of ancestral Wu1 and Omicron S in the same cell could result in the formation of S heterotrimers consisting of Wu1 and Omicron S protomers and could promote intra-S crosslinking, i.e., simultaneous binding of cross-reactive BCRs to two neighboring RBDs within the same S trimer (Figure 5—figure supplement 1). We previously postulated that intra-S crosslinking is possible for several anti-RBD IgGs based on modeling of intact IgG coordinates into single-particle cryo-electron microscopy (cryo-EM) structures of fragment antigen-binding (Fab)-S complexes (Barnes et al., 2020; Fan et al., 2022), and intra-S crosslinking was observed in EM studies of IgG-S trimer complexes (Callaway et al., 2023). However, it is currently unknown whether co-expression of Wu1 and Omicron Ss induces heterotrimerization, and if so, whether heterotrimer formation affects the overall structure of the S ectodomain and influences bivalent booster-induced immune responses.

To investigate whether S heterotrimers could form with different S protomers, we designed 6P versions (containing 6 proline substitutions to enhance expression and stability) (Hsieh et al., 2020) of Wu1/BA.1 and Wu1/BA.1/Delta soluble heterotrimer Ss (HT2 and HT3, respectively) by co-transfection with specific C-terminally-tagged constructs. HT2 was generated by co-transfecting StrepII-tagged Wu1 S and His-tagged BA.1 S, while HT3 was generated using StrepII-tagged Wu1 S, His-tagged BA.1 S, and D7324 (Sanders et al., 2013)-tagged Delta S (Figure 5A). Each heterotrimer was subsequently purified using sequential affinity purification specific to each tag, confirming the inclusion of distinct protomers in the purified heterotrimers (Figure 5A).

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HT2 and HT3 S proteins were then evaluated using single-particle cryo-EM to determine whether heterotrimeric Ss resembling their homotrimeric counterparts were formed. To ensure that C-terminal tags did not disrupt the formation of trimers, we included the following controls: (i) three homotrimers with single tags (StrepII-tagged Wu1 S, His-tagged BA.1 S, and D7324-tagged Delta S) and (ii) a homotrimer comprised of His- and StrepII-tagged protomers (Wu1-His/Wu1-StrepII). Single-particle cryo-EM analysis confirmed that all control S proteins formed trimers, indicating that C-terminal tags did not disrupt trimerization (Figure 5—figure supplement 2). Because most of the EM constructions for homotrimeric S controls exhibited preferred orientations, we determined overall conformational states (Figure 5) for the control structures but did not fit atomic models. Structural analysis also revealed trimerized HT2 and HT3 Ss (Figure 5B and C; Figure 5—figure supplement 2). Although atomic models could not be built for the HT2 and HT3 trimer reconstructions because the identities of individual protomers (Wu1 or BA.1 for HT2, and Wu1, BA.1, or Delta for HT3) could not be conclusively determined at relatively low resolution, the EM densities of S heterotrimers and control homotrimers showed no major conformational differences in domain organization (Figure 5B and C; Figure 5—figure supplement 2). As previously seen in SARS-CoV-2 S trimer structures (Walls et al., 2020; Wrapp et al., 2020), we observed two trimer populations in all datasets—one with all three RBDs in the ‘down’ conformation and one with a single RBD in an ‘up’ conformation (Figure 5D). These data demonstrate heterotrimeric S formation for soluble forms of SARS-CoV-2 S proteins. This result suggests that the bivalent S or S-EABR mRNA-LNP boost immunogens likely induce heterotrimerization, which could promote activation of cross-reactive B cells through intra-S crosslinking, a potential mechanism warranting further investigation.

The EABR mRNA vaccine platform delivers mRNA encoding engineered immunogens that induce budding of eVLPs from the plasma membrane to promote presentation of immunogens on cell surfaces and eVLPs (Hoffmann et al., 2023). This approach elicited superior neutralizing Ab responses in naïve mice compared to a conventional mRNA vaccine against original and variant SARS-CoV-2 (Hoffmann et al., 2023). However, the majority of the human population has already mounted immune responses against SARS-CoV-2 through prior vaccinations, natural infections, or a combination of both. Here, we demonstrate that the EABR mRNA vaccine approach improves humoral immune responses elicited by monovalent and bivalent mRNA-LNP booster immunizations against Omicron subvariants in pre-vaccinated mice.

The possibility of receiving a third dose of the original COVID-19 mRNA vaccine in fall 2021 (Andrews et al., 2022b) coincided with the emergence of the Omicron variants in November 2021 (WHO, 2021). These variants had acquired many substitutions, especially in the RBD, which allowed efficient evasion of Ab-mediated immunity (Liu et al., 2022; Cele et al., 2022) and rapid global spread. Similar to the effects of a third vaccination in humans (Gruell et al., 2022), a third immunization in pre-vaccinated mice with a monovalent Wu1 S mRNA-LNP booster elicited modest neutralizing activity against the early Omicron variants BA.1 and BA.5. However, the addition of an EABR sequence (Hoffmann et al., 2023) to the boosting immunogen resulted in higher Ab neutralizing titers against BA.1 and BA.5, suggesting that a monovalent Wu1 S-EABR booster could have promoted enhanced protection against early Omicron variants. Importantly, the monovalent Wu1 S-EABR mRNA-LNP booster elicited similar neutralizing responses against the BA.5, BQ.1.1, and XBB.1 subvariants compared to the conventional bivalent S mRNA-LNP booster that contained both Wu1 and BA.5 S immunogens.

While updating of mRNA vaccines can be done relatively quickly, the development, clinical testing, approval, and large-scale manufacturing of a bivalent booster that includes updated immunogens based on new circulating variants cannot be accomplished fast enough to keep up with viral evolution during a global pandemic such as COVID-19. Indeed, the Wu1/BA.5 bivalent booster became available in fall 2022, almost 1 year after the emergence of Omicron variants (Song et al., 2024). The results reported here suggest that the EABR mRNA vaccine approach presents a potential solution that could reduce the need for frequent development of updated COVID-19 boosters and potentially future pandemic viruses. Combined with our previous finding that an initial two-shot vaccination series with a Wu1 S-EABR mRNA-LNP immunogen elicited substantially higher neutralizing activity against Omicron variants than conventional Wu1 S mRNA-LNP immunizations in naïve mice (Hoffmann et al., 2023), our results demonstrate that the EABR mRNA vaccine approach has the potential to induce more effective and lasting humoral immunity against emerging SARS-CoV-2 variants and represents a promising platform for future pandemic preparedness.

Clinical studies showed that the bivalent COVID-19 mRNA booster outperformed the monovalent mRNA booster in terms of preventing symptomatic illness, hospitalizations, and deaths when administered as a fourth dose in humans (Song et al., 2024; Tan et al., 2023). Consistent with other studies (Scheaffer et al., 2023; Khoury et al., 2023; Chalkias et al., 2022; Collier et al., 2023; Davis-Gardner et al., 2023), the bivalent conventional and EABR-based boosters evaluated in this study elicited higher neutralizing responses against Omicron subvariants than their monovalent counterparts in pre-vaccinated mice, although improvements were relatively modest. However, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster consistently elicited the highest RBD binding and neutralizing titers against all tested Omicron subvariants and induced robust neutralizing responses in the highest number of animals against the BQ.1.1 and XBB.1 variants that are particularly difficult to neutralize (Wang et al., 2023c; Miller et al., 2023). These results highlight that the EABR mRNA vaccine approach and the bivalent booster strategy work synergistically to induce more effective humoral immune responses.

In addition to eliciting the most potent neutralizing responses against Omicron subvariants, the bivalent Wu1/BA.5 S-EABR mRNA-LNP booster also induced distinct DMS signatures compared to the other boost immunogens, consistent with differences in epitope mapping of polyclonal anti-RBD Ab responses. While the monovalent Wu1 S and S-EABR mRNA-LNP and the bivalent Wu1/BA.5 S mRNA-LNP boosters elicited predominantly class 1 and class 2 responses against Wu1 RBD and strong class 5 responses against XBB.1.5 RBD, boost immunizations with bivalent Wu1/BA.5 S-EABR mRNA-LNP elicited polyclass serum Ab responses against Wu1 RBD and mostly polyclass or moderate polyclass class 4 and class 5 responses against XBB.1.5 RBD. These results imply that combining the bivalent booster strategy with the EARB mRNA vaccine approach elicited a more diversified Ab response, resulting in simultaneous and balanced targeting of multiple RBD epitopes. A more diverse anti-RBD Ab response might be desirable as viral immune evasion would require mutations in multiple sites, including the more conserved class 4 and 5 RBD epitopes. As a potential mechanism for the more frequent induction of polyclass-like Ab responses, we hypothesize that EABR eVLP formation promotes close proximity of Wu1 and BA.5 S trimers on densely coated eVLPs, consistent with cryo-electron tomography imaging of purified eVLPs showing that the density of S trimers was equivalent to or higher than that on SARS-CoV-2 virions (20–40 S trimers on 40–60 nm diameter eVLPs) (Hoffmann et al., 2023). The high density of co-displayed Wu1 and BA.5 S trimers on eVLPs should facilitate inter-S crosslinking by BCRs that recognize epitopes that are conserved between Wu1 and BA.5 S trimers, leading to preferential activation of cross-reactive B cells. By comparison, conventional bivalent mRNA booster-mediated co-expression of Wu1 and BA.5 S trimers could result in lower S trimer density on cell surfaces that are crowded with endogenous membrane proteins, which could prevent efficient inter-S crosslinking.

As an additional mechanism for bivalent booster-induced preferential activation of cross-reactive B cells, we provide evidence that co-expression of ancestral and Omicron S results in heterotrimer formation that could promote intra-S crosslinking, i.e., simultaneous binding of both Fabs of a cross-reactive BCR to neighboring RBDs within the same S trimer. We previously postulated that intra-S crosslinking is possible for several anti-RBD Abs that target various RBD epitopes based on modeling of intact IgG structures onto cryo-EM structures of Fab-S complexes (Barnes et al., 2020; Fan et al., 2022). The conventional mRNA- and the EABR mRNA-based bivalent boost immunogens should promote similar degrees of heterotrimerization and intra-S crosslinking. While our RBD serum depletion assays showed that both bivalent boosters primarily elicited cross-neutralizing Abs that bind to the Wu1 and BA.5 RBDs, only the EABR mRNA-based bivalent booster induced predominantly polyclass DMS signatures. Thus, it is possible that the diversification of the anti-RBD Ab response observed for the bivalent EABR mRNA booster was primarily driven by inter-S crosslinking possibly in conjunction with intra-S crosslinking. Future studies are needed to investigate the impact of inter- and intra-S crosslinking on the activation of cross-reactive B cells and to evaluate whether the EABR mRNA vaccine approach can improve other types of bivalent and multivalent vaccines.

Although our results highlight the potential of the EABR mRNA vaccine approach in the context of pre-existing immunity, we observed that monovalent and bivalent EABR mRNA booster-induced humoral immune responses were still largely dictated by immunological imprinting resulting from the initial vaccination series. Post-boost BA.5 neutralizing responses were roughly an order of magnitude lower than Wu1 neutralization titers, even for bivalent boosters that included BA.5 S immunogens. In addition, despite eliciting consistent polyclass anti-RBD Ab responses, bivalent EABR mRNA booster-induced neutralizing activity against the BQ.1.1 and XBB.1 variants dropped over 10-fold compared to BA.5 neutralization. Notably, Ab binding responses to BQ.1.1 and XBB.1 RBDs were similar compared to BA.5 RBD binding for all boost immunogens. This discrepancy between RBD binding responses and neutralization titers indicates that only a relatively small fraction of binding Abs has neutralizing activity and/or the Abs still bind to the BQ.1.1 and XBB.1 RBDs, but fail to effectively prevent interactions with ACE2 on the surface of target cells. The initial two-shot COVID-19 mRNA vaccination series and all booster immunizations elicited potent binding responses against the S2 region, which is relatively conserved among SARS-CoV-2 variants (Li and Chang, 2023). Consistent with previous reports (Bowen et al., 2022), our depletion studies showed that anti-S2 Abs had little impact on virus neutralization, which was instead predominantly driven by anti-RBD Abs. However, anti-S2 Abs could still provide valuable immune protection against symptomatic Omicron infections through Fc-mediated effector functions (Balinsky et al., 2023). In addition, mRNA vaccines induce potent cytotoxic T cell responses that cross-recognize Omicron variants (Keeton et al., 2022) and reduce COVID-19 disease severity (Rydyznski Moderbacher et al., 2020).

Taken together, our results demonstrate that the EABR mRNA vaccine approach improves monovalent and bivalent booster-mediated humoral immune responses against Omicron subvariants in pre-vaccinated mice. DMS epitope mapping studies further showed that the bivalent EABR mRNA booster elicited a more diversified anti-RBD Ab response than all other tested boost immunogens. Our work also provides evidence that bivalent mRNA booster immunizations promote heterotrimer formation, which could activate cross-reactive B cells through intra-S crosslinking. Despite these advances, future work is needed to develop booster strategies that overcome immunological imprinting more effectively and confer lasting immunity against emerging variants.

Code used for data processing and visualization of DMS results is available at data.caltech.edu (DOI: https://doi.org/10.22002/j4k4w-p8331). DMS raw sequencing data is available under an NCBI SRA (BioProject: PRJNA1067836; BioSample: SAMN56741139; SRA: SRX32770151). Cryo-EM density maps are deposited in the EMDB with accession codes: EMD-71513, EMD-71514, EMD-71515 and EMD-71516. Materials are available upon request to corresponding authors with a signed material transfer agreement, and other information required to analyze the data in this paper is available from the lead contacts upon request. This paper does not report original code.

1. 1. California Institute of Technology

   (2026) NCBI Sequence Read Archive

   ID SRX32770151. SARS-CoV-2 RBD mutational antig Illumina barcode sequencing for XBB15_22_gp8_81_250_abneg.

   https://www.ncbi.nlm.nih.gov/sra/SRX32770151
2. 1. Fan C
   2. Dam KA
   3. Bjorkman PJ

   (2025) EMDataBank

   ID EMD-71513. SARS-CoV-2 Wuhan-Hu-1/BA.1 spike heterotrimer (HT2) with 3-'down' RBDs.

   https://emdataresource.org/EMD-71513
3. 1. Fan C
   2. Dam KA
   3. Bjorkman PJ

   (2025) EMDataBank

   ID EMD-71514. SARS-CoV-2 Wuhan-Hu-1/BA.1 spike heterotrimer (HT2) with 1-'up' RBD.

   https://emdataresource.org/EMD-71514
4. 1. Fan C
   2. Dam KA
   3. Bjorkman PJ

   (2025) EMDataBank

   ID EMD-71515. SARS-CoV-2 Wuhan-Hu-1/BA.1/Delta spike heterotrimer (HT3) with 3-'down' RBDs.

   https://emdataresource.org/EMD-71515
5. 1. Fan C
   2. Dam KA
   3. Bjorkman PJ

   (2025) EMDataBank

   ID EMD-71516. SARS-CoV-2 Wuhan-Hu-1/BA.1/Delta spike heterotrimer (HT3) with 1-'up' RBD.

   https://emdataresource.org/EMD-71516

1. 1. Alsoussi WB
   2. Malladi SK
   3. Zhou JQ
   4. Liu Z
   5. Ying B
   6. Kim W
   7. Schmitz AJ
   8. Lei T
   9. Horvath SC
   10. Sturtz AJ
   11. McIntire KM
   12. Evavold B
   13. Han F
   14. Scheaffer SM
   15. Fox IF
   16. Mirza SF
   17. Parra-Rodriguez L
   18. Nachbagauer R
   19. Nestorova B
   20. Chalkias S
   21. Farnsworth CW
   22. Klebert MK
   23. Pusic I
   24. Strnad BS
   25. Middleton WD
   26. Teefey SA
   27. Whelan SPJ
   28. Diamond MS
   29. Paris R
   30. O’Halloran JA
   31. Presti RM
   32. Turner JS
   33. Ellebedy AH

   (2023) SARS-CoV-2 Omicron boosting induces de novo B cell response in humans

   Nature 617:592–598.

   https://doi.org/10.1038/s41586-023-06025-4

   • PubMed
   • Google Scholar
2. 1. Andrews N
   2. Stowe J
   3. Kirsebom F
   4. Toffa S
   5. Rickeard T
   6. Gallagher E
   7. Gower C
   8. Kall M
   9. Groves N
   10. O’Connell A-M
   11. Simons D
   12. Blomquist PB
   13. Zaidi A
   14. Nash S
   15. Iwani Binti Abdul Aziz N
   16. Thelwall S
   17. Dabrera G
   18. Myers R
   19. Amirthalingam G
   20. Gharbia S
   21. Barrett JC
   22. Elson R
   23. Ladhani SN
   24. Ferguson N
   25. Zambon M
   26. Campbell CNJ
   27. Brown K
   28. Hopkins S
   29. Chand M
   30. Ramsay M
   31. Lopez Bernal J

   (2022a) Covid-19 vaccine effectiveness against the Omicron (B.1.1.529) variant

   The New England Journal of Medicine 386:1532–1546.

   https://doi.org/10.1056/NEJMoa2119451

   • PubMed
   • Google Scholar
3. 1. Andrews N
   2. Stowe J
   3. Kirsebom F
   4. Toffa S
   5. Sachdeva R
   6. Gower C
   7. Ramsay M
   8. Lopez Bernal J

   (2022b) Effectiveness of COVID-19 booster vaccines against COVID-19-related symptoms, hospitalization and death in England

   Nature Medicine 28:831–837.

   https://doi.org/10.1038/s41591-022-01699-1

   • PubMed
   • Google Scholar
4. 1. Baden LR
   2. El Sahly HM
   3. Essink B
   4. Kotloff K
   5. Frey S
   6. Novak R
   7. Diemert D
   8. Spector SA
   9. Rouphael N
   10. Creech CB
   11. McGettigan J
   12. Khetan S
   13. Segall N
   14. Solis J
   15. Brosz A
   16. Fierro C
   17. Schwartz H
   18. Neuzil K
   19. Corey L
   20. Gilbert P
   21. Janes H
   22. Follmann D
   23. Marovich M
   24. Mascola J
   25. Polakowski L
   26. Ledgerwood J
   27. Graham BS
   28. Bennett H
   29. Pajon R
   30. Knightly C
   31. Leav B
   32. Deng W
   33. Zhou H
   34. Han S
   35. Ivarsson M
   36. Miller J
   37. Zaks T

   (2021) Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine

   New England Journal of Medicine 384:403–416.

   https://doi.org/10.1056/NEJMoa2035389

   • Google Scholar
5. 1. Balinsky CA
   2. Jiang L
   3. Jani V
   4. Cheng Y
   5. Zhang Z
   6. Belinskaya T
   7. Qiu Q
   8. Long TK
   9. Schilling MA
   10. Jenkins SA
   11. Corson KS
   12. Martin NJ
   13. Letizia AG
   14. Hontz RD
   15. Sun P

   (2023) Antibodies to S2 domain of SARS-CoV-2 spike protein in Moderna mRNA vaccinated subjects sustain antibody-dependent NK cell-mediated cell cytotoxicity against Omicron BA.1

   Frontiers in Immunology 14:1266829.

   https://doi.org/10.3389/fimmu.2023.1266829

   • PubMed
   • Google Scholar
6. 1. Barnes CO
   2. Jette CA
   3. Abernathy ME
   4. Dam KMA
   5. Esswein SR
   6. Gristick HB
   7. Malyutin AG
   8. Sharaf NG
   9. Huey-Tubman KE
   10. Lee YE
   11. Robbiani DF
   12. Nussenzweig MC
   13. West AP Jr
   14. Bjorkman PJ

   (2020) SARS-CoV-2 neutralizing antibody structures inform therapeutic strategies

   Nature 588:682–687.

   https://doi.org/10.1038/s41586-020-2852-1

   • PubMed
   • Google Scholar
7. 1. Bowen JE
   2. Park YJ
   3. Stewart C
   4. Brown JT
   5. Sharkey WK
   6. Walls AC
   7. Joshi A
   8. Sprouse KR
   9. McCallum M
   10. Tortorici MA
   11. Franko NM
   12. Logue JK
   13. Mazzitelli IG
   14. Nguyen AW
   15. Silva RP
   16. Huang Y
   17. Low JS
   18. Jerak J
   19. Tiles SW
   20. Ahmed K
   21. Shariq A
   22. Dan JM
   23. Zhang Z
   24. Weiskopf D
   25. Sette A
   26. Snell G
   27. Posavad CM
   28. Iqbal NT
   29. Geffner J
   30. Bandera A
   31. Gori A
   32. Sallusto F
   33. Maynard JA
   34. Crotty S
   35. Van Voorhis WC
   36. Simmerling C
   37. Grifantini R
   38. Chu HY
   39. Corti D
   40. Veesler D

   (2022) SARS-CoV-2 spike conformation determines plasma neutralizing activity elicited by a wide panel of human vaccines

   Science Immunology 7:eadf1421.

   https://doi.org/10.1126/sciimmunol.adf1421

   • PubMed
   • Google Scholar
8. 1. Callaway HM
   2. Hastie KM
   3. Schendel SL
   4. Li H
   5. Yu X
   6. Shek J
   7. Buck T
   8. Hui S
   9. Bedinger D
   10. Troup C
   11. Dennison SM
   12. Li K
   13. Alpert MD
   14. Bailey CC
   15. Benzeno S
   16. Bonnevier JL
   17. Chen JQ
   18. Chen C
   19. Cho H
   20. Crompton PD
   21. Dussupt V
   22. Entzminger KC
   23. Ezzyat Y
   24. Fleming JK
   25. Geukens N
   26. Gilbert AE
   27. Guan Y
   28. Han X
   29. Harvey CJ
   30. Hatler JM
   31. Howie B
   32. Hu C
   33. Huang A
   34. Imbrechts M
   35. Jin A
   36. Kamachi N
   37. Keitany G
   38. Klinger M
   39. Kolls JK
   40. Krebs SJ
   41. Li T
   42. Luo F
   43. Maruyama T
   44. Meehl MA
   45. Mendez-Rivera L
   46. Musa A
   47. Okumura CJ
   48. Rubin BER
   49. Sato AK
   50. Shen M
   51. Singh A
   52. Song S
   53. Tan J
   54. Trimarchi JM
   55. Upadhyay DP
   56. Wang Y
   57. Yu L
   58. Yuan TZ
   59. Yusko E
   60. Peters B
   61. Tomaras G
   62. Saphire EO

   (2023) Bivalent intra-spike binding provides durability against emergent Omicron lineages: Results from a global consortium

   Cell Reports 42:112014.

   https://doi.org/10.1016/j.celrep.2023.112014

   • PubMed
   • Google Scholar
9. 1. Carreño JM
   2. Singh G
   3. Simon V
   4. Krammer F
   5. PVI study group

   (2023) Bivalent COVID-19 booster vaccines and the absence of BA.5-specific antibodies

   The Lancet. Microbe 4:e569.

   https://doi.org/10.1016/S2666-5247(23)00118-0

   • PubMed
   • Google Scholar
10. 1. Cele S
    2. Jackson L
    3. Khoury DS
    4. Khan K
    5. Moyo-Gwete T
    6. Tegally H
    7. San JE
    8. Cromer D
    9. Scheepers C
    10. Amoako DG
    11. Karim F
    12. Bernstein M
    13. Lustig G
    14. Archary D
    15. Smith M
    16. Ganga Y
    17. Jule Z
    18. Reedoy K
    19. Hwa SH
    20. Giandhari J
    21. Blackburn JM
    22. Gosnell BI
    23. Abdool Karim SS
    24. Hanekom W
    25. Davies MA
    26. Hsiao M
    27. Martin D
    28. Mlisana K
    29. Wibmer CK
    30. Williamson C
    31. York D
    32. Harrichandparsad R
    33. Herbst K
    34. Jeena P
    35. Khoza T
    36. Kløverpris H
    37. Leslie A
    38. Madansein R
    39. Magula N
    40. Manickchund N
    41. Marakalala M
    42. Mazibuko M
    43. Moshabela M
    44. Mthabela N
    45. Naidoo K
    46. Ndhlovu Z
    47. Ndung’u T
    48. Ngcobo N
    49. Nyamande K
    50. Patel V
    51. Smit T
    52. Steyn A
    53. Wong E
    54. von Gottberg A
    55. Bhiman JN
    56. Lessells RJ
    57. Moosa MYS
    58. Davenport MP
    59. de Oliveira T
    60. Moore PL
    61. Sigal A
    62. NGS-SA
    63. COMMIT-KZN Team

    (2022) Omicron extensively but incompletely escapes Pfizer BNT162b2 neutralization

    Nature 602:654–656.

    https://doi.org/10.1038/s41586-021-04387-1

    • Google Scholar
11. 1. Chalkias S
    2. Harper C
    3. Vrbicky K
    4. Walsh SR
    5. Essink B
    6. Brosz A
    7. McGhee N
    8. Tomassini JE
    9. Chen X
    10. Chang Y
    11. Sutherland A
    12. Montefiori DC
    13. Girard B
    14. Edwards DK
    15. Feng J
    16. Zhou H
    17. Baden LR
    18. Miller JM
    19. Das R

    (2022) A bivalent Omicron-containing booster vaccine against Covid-19

    The New England Journal of Medicine 387:1279–1291.

    https://doi.org/10.1056/NEJMoa2208343

    • PubMed
    • Google Scholar
12. 1. Chen Y
    2. Zhao X
    3. Zhou H
    4. Zhu H
    5. Jiang S
    6. Wang P

    (2023) Broadly neutralizing antibodies to SARS-CoV-2 and other human coronaviruses

    Nature Reviews. Immunology 23:189–199.

    https://doi.org/10.1038/s41577-022-00784-3

    • PubMed
    • Google Scholar
13. 1. Cobey S
    2. Hensley SE

    (2017) Immune history and influenza virus susceptibility

    Current Opinion in Virology 22:105–111.

    https://doi.org/10.1016/j.coviro.2016.12.004

    • PubMed
    • Google Scholar
14. 1. Cohen AA
    2. Gnanapragasam PNP
    3. Lee YE
    4. Hoffman PR
    5. Ou S
    6. Kakutani LM
    7. Keeffe JR
    8. Wu HJ
    9. Howarth M
    10. West AP
    11. Barnes CO
    12. Nussenzweig MC
    13. Bjorkman PJ

    (2021) Mosaic nanoparticles elicit cross-reactive immune responses to zoonotic coronaviruses in mice

    Science 371:735–741.

    https://doi.org/10.1126/science.abf6840

    • Google Scholar
15. 1. Cohen AA
    2. van Doremalen N
    3. Greaney AJ
    4. Andersen H
    5. Sharma A
    6. Starr TN
    7. Keeffe JR
    8. Fan C
    9. Schulz JE
    10. Gnanapragasam PNP
    11. Kakutani LM
    12. West AP
    13. Saturday G
    14. Lee YE
    15. Gao H
    16. Jette CA
    17. Lewis MG
    18. Tan TK
    19. Townsend AR
    20. Bloom JD
    21. Munster VJ
    22. Bjorkman PJ

    (2022) Mosaic RBD nanoparticles protect against challenge by diverse sarbecoviruses in animal models

    Science 377:eabq0839.

    https://doi.org/10.1126/science.abq0839

    • Google Scholar
16. 1. Cohen AA
    2. Keeffe JR
    3. Schiepers A
    4. Dross SE
    5. Greaney AJ
    6. Rorick AV
    7. Gao H
    8. Gnanapragasam PNP
    9. Fan C
    10. West AP Jr
    11. Ramsingh AI
    12. Erasmus JH
    13. Pata JD
    14. Muramatsu H
    15. Pardi N
    16. Lin PJC
    17. Baxter S
    18. Cruz R
    19. Quintanar-Audelo M
    20. Robb E
    21. Serrano-Amatriain C
    22. Magneschi L
    23. Fotheringham IG
    24. Fuller DH
    25. Victora GD
    26. Bjorkman PJ

    (2024) Mosaic sarbecovirus nanoparticles elicit cross-reactive responses in pre-vaccinated animals

    Cell 187:5554–5571.

    https://doi.org/10.1016/j.cell.2024.07.052

    • PubMed
    • Google Scholar
17. 1. Collier ARY
    2. Miller J
    3. Hachmann NP
    4. McMahan K
    5. Liu J
    6. Bondzie EA
    7. Gallup L
    8. Rowe M
    9. Schonberg E
    10. Thai S
    11. Barrett J
    12. Borducchi EN
    13. Bouffard E
    14. Jacob-Dolan C
    15. Mazurek CR
    16. Mutoni A
    17. Powers O
    18. Sciacca M
    19. Surve N
    20. VanWyk H
    21. Wu C
    22. Barouch DH

    (2023) Immunogenicity of BA.5 bivalent mRNA vaccine boosters

    The New England Journal of Medicine 388:565–567.

    https://doi.org/10.1056/NEJMc2213948

    • PubMed
    • Google Scholar
18. 1. Corbett KS
    2. Edwards DK
    3. Leist SR
    4. Abiona OM
    5. Boyoglu-Barnum S
    6. Gillespie RA
    7. Himansu S
    8. Schäfer A
    9. Ziwawo CT
    10. DiPiazza AT
    11. Dinnon KH
    12. Elbashir SM
    13. Shaw CA
    14. Woods A
    15. Fritch EJ
    16. Martinez DR
    17. Bock KW
    18. Minai M
    19. Nagata BM
    20. Hutchinson GB
    21. Wu K
    22. Henry C
    23. Bahl K
    24. Garcia-Dominguez D
    25. Ma L
    26. Renzi I
    27. Kong WP
    28. Schmidt SD
    29. Wang L
    30. Zhang Y
    31. Phung E
    32. Chang LA
    33. Loomis RJ
    34. Altaras NE
    35. Narayanan E
    36. Metkar M
    37. Presnyak V
    38. Liu C
    39. Louder MK
    40. Shi W
    41. Leung K
    42. Yang ES
    43. West A
    44. Gully KL
    45. Stevens LJ
    46. Wang N
    47. Wrapp D
    48. Doria-Rose NA
    49. Stewart-Jones G
    50. Bennett H
    51. Alvarado GS
    52. Nason MC
    53. Ruckwardt TJ
    54. McLellan JS
    55. Denison MR
    56. Chappell JD
    57. Moore IN
    58. Morabito KM
    59. Mascola JR
    60. Baric RS
    61. Carfi A
    62. Graham BS

    (2020) SARS-CoV-2 mRNA vaccine design enabled by prototype pathogen preparedness

    Nature 586:567–571.

    https://doi.org/10.1038/s41586-020-2622-0

    • PubMed
    • Google Scholar
19. 1. Crawford KHD
    2. Eguia R
    3. Dingens AS
    4. Loes AN
    5. Malone KD
    6. Wolf CR
    7. Chu HY
    8. Tortorici MA
    9. Veesler D
    10. Murphy M
    11. Pettie D
    12. King NP
    13. Balazs AB
    14. Bloom JD

    (2020) Protocol and reagents for Pseudotyping lentiviral particles with SARS-CoV-2 spike protein for neutralization assays

    Viruses 12:513.

    https://doi.org/10.3390/v12050513

    • Google Scholar
20. 1. Davis-Gardner ME
    2. Lai L
    3. Wali B
    4. Samaha H
    5. Solis D
    6. Lee M
    7. Porter-Morrison A
    8. Hentenaar IT
    9. Yamamoto F
    10. Godbole S
    11. Liu Y
    12. Douek DC
    13. Lee FEH
    14. Rouphael N
    15. Moreno A
    16. Pinsky BA
    17. Suthar MS

    (2023) Neutralization against BA.2.75.2, BQ.1.1, and XBB from mRNA bivalent booster

    The New England Journal of Medicine 388:183–185.

    https://doi.org/10.1056/NEJMc2214293

    • PubMed
    • Google Scholar
21. 1. Fan C
    2. Cohen AA
    3. Park M
    4. Hung AFH
    5. Keeffe JR
    6. Gnanapragasam PNP
    7. Lee YE
    8. Gao H
    9. Kakutani LM
    10. Wu Z
    11. Kleanthous H
    12. Malecek KE
    13. Williams JC
    14. Bjorkman PJ

    (2022) Neutralizing monoclonal antibodies elicited by mosaic RBD nanoparticles bind conserved sarbecovirus epitopes

    Immunity 55:2419–2435.

    https://doi.org/10.1016/j.immuni.2022.10.019

    • PubMed
    • Google Scholar
22. 1. Fan C
    2. Keeffe JR
    3. Malecek KE
    4. Cohen AA
    5. West AP Jr
    6. Baharani VA
    7. Rorick AV
    8. Gao H
    9. Gnanapragasam PNP
    10. Rho S
    11. Alvarez J
    12. Segovia LN
    13. Hatziioannou T
    14. Bieniasz PD
    15. Bjorkman PJ

    (2025) Cross-reactive sarbecovirus antibodies induced by mosaic RBD nanoparticles

    PNAS 122:e2501637122.

    https://doi.org/10.1073/pnas.2501637122

    • PubMed
    • Google Scholar
23. 1. Feng S
    2. Phillips DJ
    3. White T
    4. Sayal H
    5. Aley PK
    6. Bibi S
    7. Dold C
    8. Fuskova M
    9. Gilbert SC
    10. Hirsch I
    11. Humphries HE
    12. Jepson B
    13. Kelly EJ
    14. Plested E
    15. Shoemaker K
    16. Thomas KM
    17. Vekemans J
    18. Villafana TL
    19. Lambe T
    20. Pollard AJ
    21. Voysey M
    22. Oxford COVID Vaccine Trial Group

    (2021) Correlates of protection against symptomatic and asymptomatic SARS-CoV-2 infection

    Nature Medicine 27:2032–2040.

    https://doi.org/10.1038/s41591-021-01540-1

    • PubMed
    • Google Scholar
24. 1. Greaney AJ
    2. Loes AN
    3. Crawford KHD
    4. Starr TN
    5. Malone KD
    6. Chu HY
    7. Bloom JD

    (2021a) Comprehensive mapping of mutations in the SARS-CoV-2 receptor-binding domain that affect recognition by polyclonal human plasma antibodies

    Cell Host & Microbe 29:463–476.

    https://doi.org/10.1016/j.chom.2021.02.003

    • Google Scholar
25. 1. Greaney AJ
    2. Starr TN
    3. Barnes CO
    4. Weisblum Y
    5. Schmidt F
    6. Caskey M
    7. Gaebler C

    (2021b) Mapping mutations to the SARS-CoV-2 RBD that escape binding by different classes of antibodies

    Nature Communications 12:4196.

    https://doi.org/10.1038/s41467-021-24435-8

    • Google Scholar
26. 1. Gruell H
    2. Vanshylla K
    3. Tober-Lau P
    4. Hillus D
    5. Schommers P
    6. Lehmann C
    7. Kurth F
    8. Sander LE
    9. Klein F

    (2022) mRNA booster immunization elicits potent neutralizing serum activity against the SARS-CoV-2 Omicron variant

    Nature Medicine 28:477–480.

    https://doi.org/10.1038/s41591-021-01676-0

    • PubMed
    • Google Scholar
27. 1. Hills RA
    2. Tan TK
    3. Cohen AA
    4. Keeffe JR
    5. Keeble AH
    6. Gnanapragasam PNP
    7. Storm KN
    8. Rorick AV
    9. West AP Jr
    10. Hill ML
    11. Liu S
    12. Gilbert-Jaramillo J
    13. Afzal M
    14. Napier A
    15. Admans G
    16. James WS
    17. Bjorkman PJ
    18. Townsend AR
    19. Howarth MR

    (2024) Proactive vaccination using multiviral Quartet Nanocages to elicit broad anti-coronavirus responses

    Nature Nanotechnology 19:1216–1223.

    https://doi.org/10.1038/s41565-024-01655-9

    • PubMed
    • Google Scholar
28. 1. Hoffmann MAG
    2. Yang Z
    3. Huey-Tubman KE
    4. Cohen AA
    5. Gnanapragasam PNP
    6. Nakatomi LM
    7. Storm KN
    8. Moon WJ
    9. Lin PJC
    10. West AP
    11. Bjorkman PJ

    (2023) ESCRT recruitment to SARS-CoV-2 spike induces virus-like particles that improve mRNA vaccines

    Cell 186:2380–2391.

    https://doi.org/10.1016/j.cell.2023.04.024

    • Google Scholar
29. 1. Hogan MJ
    2. Pardi N

    (2022) mRNA Vaccines in the COVID-19 Pandemic and Beyond

    Annual Review of Medicine 73:17–39.

    https://doi.org/10.1146/annurev-med-042420-112725

    • PubMed
    • Google Scholar
30. 1. Hsieh CL
    2. Goldsmith JA
    3. Schaub JM
    4. DiVenere AM
    5. Kuo HC
    6. Javanmardi K
    7. Le KC
    8. Wrapp D
    9. Lee AG
    10. Liu Y
    11. Chou CW
    12. Byrne PO
    13. Hjorth CK
    14. Johnson NV
    15. Ludes-Meyers J
    16. Nguyen AW
    17. Park J
    18. Wang N
    19. Amengor D
    20. Lavinder JJ
    21. Ippolito GC
    22. Maynard JA
    23. Finkelstein IJ
    24. McLellan JS

    (2020) Structure-based design of prefusion-stabilized SARS-CoV-2 spikes

    Science 369:1501–1505.

    https://doi.org/10.1126/science.abd0826

    • Google Scholar
31. 1. Hsieh CL
    2. Leist SR
    3. Miller EH
    4. Zhou L
    5. Powers JM
    6. Tse AL
    7. Wang A
    8. West A
    9. Zweigart MR
    10. Schisler JC
    11. Jangra RK
    12. Chandran K
    13. Baric RS
    14. McLellan JS

    (2024) Prefusion-stabilized SARS-CoV-2 S2-only antigen provides protection against SARS-CoV-2 challenge

    Nature Communications 15:1553.

    https://doi.org/10.1038/s41467-024-45404-x

    • PubMed
    • Google Scholar
32. 1. Karikó K
    2. Muramatsu H
    3. Welsh FA
    4. Ludwig J
    5. Kato H
    6. Akira S
    7. Weissman D

    (2008) Incorporation of pseudouridine into mRNA yields superior nonimmunogenic vector with increased translational capacity and biological stability

    Molecular Therapy 16:1833–1840.

    https://doi.org/10.1038/mt.2008.200

    • PubMed
    • Google Scholar
33. 1. Karikó K
    2. Muramatsu H
    3. Ludwig J
    4. Weissman D

    (2011) Generating the optimal mRNA for therapy: HPLC purification eliminates immune activation and improves translation of nucleoside-modified, protein-encoding mRNA

    Nucleic Acids Research 39:e142.

    https://doi.org/10.1093/nar/gkr695

    • PubMed
    • Google Scholar
34. 1. Keeton R
    2. Tincho MB
    3. Ngomti A
    4. Baguma R
    5. Benede N
    6. Suzuki A
    7. Khan K
    8. Cele S
    9. Bernstein M
    10. Karim F
    11. Madzorera SV
    12. Moyo-Gwete T
    13. Mennen M
    14. Skelem S
    15. Adriaanse M
    16. Mutithu D
    17. Aremu O
    18. Stek C
    19. du Bruyn E
    20. Van Der Mescht MA
    21. de Beer Z
    22. de Villiers TR
    23. Bodenstein A
    24. van den Berg G
    25. Mendes A
    26. Strydom A
    27. Venter M
    28. Giandhari J
    29. Naidoo Y
    30. Pillay S
    31. Tegally H
    32. Grifoni A
    33. Weiskopf D
    34. Sette A
    35. Wilkinson RJ
    36. de Oliveira T
    37. Bekker LG
    38. Gray G
    39. Ueckermann V
    40. Rossouw T
    41. Boswell MT
    42. Bhiman JN
    43. Moore PL
    44. Sigal A
    45. Ntusi NAB
    46. Burgers WA
    47. Riou C

    (2022) T cell responses to SARS-CoV-2 spike cross-recognize Omicron

    Nature 603:488–492.

    https://doi.org/10.1038/s41586-022-04460-3

    • PubMed
    • Google Scholar
35. 1. Khoury DS
    2. Docken SS
    3. Subbarao K
    4. Kent SJ
    5. Davenport MP
    6. Cromer D

    (2023) Predicting the efficacy of variant-modified COVID-19 vaccine boosters

    Nature Medicine 29:574–578.

    https://doi.org/10.1038/s41591-023-02228-4

    • PubMed
    • Google Scholar
36. 1. Korber B
    2. Fischer WM
    3. Gnanakaran S
    4. Yoon H
    5. Theiler J
    6. Abfalterer W
    7. Hengartner N
    8. Giorgi EE
    9. Bhattacharya T
    10. Foley B
    11. Hastie KM
    12. Parker MD
    13. Partridge DG
    14. Evans CM
    15. Freeman TM
    16. de Silva TI
    17. Angyal A
    18. Brown RL
    19. Carrilero L
    20. Green LR
    21. Groves DC
    22. Johnson KJ
    23. Keeley AJ
    24. Lindsey BB
    25. Parsons PJ
    26. Raza M
    27. Rowland-Jones S
    28. Smith N
    29. Tucker RM
    30. Wang D
    31. Wyles MD
    32. McDanal C
    33. Perez LG
    34. Tang H
    35. Moon-Walker A
    36. Whelan SP
    37. LaBranche CC
    38. Saphire EO
    39. Montefiori DC

    (2020) Tracking changes in SARS-CoV-2 Spike: Evidence that D614G increases infectivity of the COVID-19 virus

    Cell 182:812–827.

    https://doi.org/10.1016/j.cell.2020.06.043

    • Google Scholar
37. 1. Landau M
    2. Mayrose I
    3. Rosenberg Y
    4. Glaser F
    5. Martz E
    6. Pupko T
    7. Ben-Tal N

    (2005) ConSurf 2005: The projection of evolutionary conservation scores of residues on protein structures

    Nucleic Acids Research 33:W299–W302.

    https://doi.org/10.1093/nar/gki370

    • PubMed
    • Google Scholar
38. 1. Li CJ
    2. Chang SC

    (2023) SARS-CoV-2 spike S2-specific neutralizing antibodies

    Emerging Microbes & Infections 12:2220582.

    https://doi.org/10.1080/22221751.2023.2220582

    • Google Scholar
39. 1. Liu L
    2. Iketani S
    3. Guo Y
    4. Chan JFW
    5. Wang M
    6. Liu L
    7. Luo Y
    8. Chu H
    9. Huang Y
    10. Nair MS
    11. Yu J
    12. Chik KKH
    13. Yuen TTT
    14. Yoon C
    15. To KKW
    16. Chen H
    17. Yin MT
    18. Sobieszczyk ME
    19. Huang Y
    20. Wang HH
    21. Sheng Z
    22. Yuen KY
    23. Ho DD

    (2022) Striking antibody evasion manifested by the Omicron variant of SARS-CoV-2

    Nature 602:676–681.

    https://doi.org/10.1038/s41586-021-04388-0

    • PubMed
    • Google Scholar
40. 1. Mastronarde DN

    (2005) Automated electron microscope tomography using robust prediction of specimen movements

    Journal of Structural Biology 152:36–51.

    https://doi.org/10.1016/j.jsb.2005.07.007

    • Google Scholar
41. 1. McBride CE
    2. Li J
    3. Machamer CE

    (2007) The Cytoplasmic tail of the severe acute respiratory syndrome coronavirus spike protein contains a novel endoplasmic reticulum retrieval signal that binds COPI and promotes interaction with membrane protein

    Journal of Virology 81:2418–2428.

    https://doi.org/10.1128/JVI.02146-06

    • Google Scholar
42. 1. Miettinen HM
    2. Rose JK
    3. Mellman I

    (1989) Fc receptor isoforms exhibit distinct abilities for coated pit localization as a result of cytoplasmic domain heterogeneity

    Cell 58:317–327.

    https://doi.org/10.1016/0092-8674(89)90846-5

    • Google Scholar
43. 1. Miller J
    2. Hachmann NP
    3. Collier AY
    4. Lasrado N
    5. Mazurek CR
    6. Patio RC
    7. Powers O
    8. Surve N
    9. Theiler J
    10. Korber B
    11. Barouch DH

    (2023) Substantial neutralization escape by SARS-CoV-2 Omicron variants BQ.1.1 and XBB.1

    New England Journal of Medicine 388:662–664.

    https://doi.org/10.1056/NEJMc2214314

    • Google Scholar
44. 1. Muik A
    2. Lui BG
    3. Bacher M
    4. Wallisch AK
    5. Toker A
    6. Couto CIC
    7. Güler A
    8. Mampilli V
    9. Schmitt GJ
    10. Mottl J
    11. Ziegenhals T
    12. Fesser S
    13. Reinholz J
    14. Wernig F
    15. Schraut KG
    16. Hefesha H
    17. Cai H
    18. Yang Q
    19. Walzer KC
    20. Grosser J
    21. Strauss S
    22. Finlayson A
    23. Krüger K
    24. Ozhelvaci O
    25. Grikscheit K
    26. Kohmer N
    27. Ciesek S
    28. Swanson KA
    29. Vogel AB
    30. Türeci Ö
    31. Sahin U

    (2022) Exposure to BA.4/5 S protein drives neutralization of Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5 in vaccine-experienced humans and mice

    Science Immunology 7:eade9888.

    https://doi.org/10.1126/sciimmunol.ade9888

    • PubMed
    • Google Scholar
45. 1. Oberhardt V
    2. Luxenburger H
    3. Kemming J
    4. Schulien I
    5. Ciminski K
    6. Giese S
    7. Csernalabics B
    8. Lang-Meli J
    9. Janowska I
    10. Staniek J
    11. Wild K
    12. Basho K
    13. Marinescu MS
    14. Fuchs J
    15. Topfstedt F
    16. Janda A
    17. Sogukpinar O
    18. Hilger H
    19. Stete K
    20. Emmerich F
    21. Bengsch B
    22. Waller CF
    23. Rieg S
    24. Boettler T
    25. Zoldan K
    26. Kochs G
    27. Schwemmle M
    28. Rizzi M
    29. Thimme R
    30. Neumann-Haefelin C
    31. Hofmann M

    (2021) Rapid and stable mobilization of CD8+ T cells by SARS-CoV-2 mRNA vaccine

    Nature 597:268–273.

    https://doi.org/10.1038/s41586-021-03841-4

    • Google Scholar
46. 1. Painter MM
    2. Mathew D
    3. Goel RR
    4. Apostolidis SA
    5. Pattekar A
    6. Kuthuru O
    7. Baxter AE
    8. Herati RS
    9. Oldridge DA
    10. Gouma S
    11. Hicks P
    12. Dysinger S
    13. Lundgreen KA
    14. Kuri-Cervantes L
    15. Adamski S
    16. Hicks A
    17. Korte S
    18. Giles JR
    19. Weirick ME
    20. McAllister CM
    21. Dougherty J
    22. Long S
    23. D’Andrea K
    24. Hamilton JT
    25. Betts MR
    26. Bates P
    27. Hensley SE
    28. Grifoni A
    29. Weiskopf D
    30. Sette A
    31. Greenplate AR
    32. Wherry EJ

    (2021) Rapid induction of antigen-specific CD4⁺ T cells is associated with coordinated humoral and cellular immunity to SARS-CoV-2 mRNA vaccination

    Immunity 54:2133–2142.

    https://doi.org/10.1016/j.immuni.2021.08.001

    • PubMed
    • Google Scholar
47. 1. Pallesen J
    2. Wang N
    3. Corbett KS
    4. Wrapp D
    5. Kirchdoerfer RN
    6. Turner HL
    7. Cottrell CA
    8. Becker MM
    9. Wang L
    10. Shi W
    11. Kong WP
    12. Andres EL
    13. Kettenbach AN
    14. Denison MR
    15. Chappell JD
    16. Graham BS
    17. Ward AB
    18. McLellan JS

    (2017) Immunogenicity and structures of a rationally designed prefusion MERS-CoV spike antigen

    PNAS 114:E7348–E7357.

    https://doi.org/10.1073/pnas.1707304114

    • Google Scholar
48. 1. Pardi N
    2. Tuyishime S
    3. Muramatsu H
    4. Kariko K
    5. Mui BL
    6. Tam YK
    7. Madden TD
    8. Hope MJ
    9. Weissman D

    (2015) Expression kinetics of nucleoside-modified mRNA delivered in lipid nanoparticles to mice by various routes

    Journal of Controlled Release 217:345–351.

    https://doi.org/10.1016/j.jconrel.2015.08.007

    • PubMed
    • Google Scholar
49. 1. Park YJ
    2. Pinto D
    3. Walls AC
    4. Liu Z
    5. De Marco A
    6. Benigni F
    7. Zatta F
    8. Silacci-Fregni C
    9. Bassi J
    10. Sprouse KR
    11. Addetia A
    12. Bowen JE
    13. Stewart C
    14. Giurdanella M
    15. Saliba C
    16. Guarino B
    17. Schmid MA
    18. Franko NM
    19. Logue JK
    20. Dang HV
    21. Hauser K
    22. di Iulio J
    23. Rivera W
    24. Schnell G
    25. Rajesh A
    26. Zhou J
    27. Farhat N
    28. Kaiser H
    29. Montiel-Ruiz M
    30. Noack J
    31. Lempp FA
    32. Janer J
    33. Abdelnabi R
    34. Maes P
    35. Ferrari P
    36. Ceschi A
    37. Giannini O
    38. de Melo GD
    39. Kergoat L
    40. Bourhy H
    41. Neyts J
    42. Soriaga L
    43. Purcell LA
    44. Snell G
    45. Whelan SPJ
    46. Lanzavecchia A
    47. Virgin HW
    48. Piccoli L
    49. Chu HY
    50. Pizzuto MS
    51. Corti D
    52. Veesler D

    (2022) Imprinted antibody responses against SARS-CoV-2 Omicron sublineages

    Science 378:619–627.

    https://doi.org/10.1126/science.adc9127

    • PubMed
    • Google Scholar
50. 1. Pinto D
    2. Sauer MM
    3. Czudnochowski N
    4. Low JS
    5. Tortorici MA
    6. Housley MP
    7. Noack J
    8. Walls AC
    9. Bowen JE
    10. Guarino B
    11. Rosen LE
    12. di Iulio J
    13. Jerak J
    14. Kaiser H
    15. Islam S
    16. Jaconi S
    17. Sprugasci N
    18. Culap K
    19. Abdelnabi R
    20. Foo C
    21. Coelmont L
    22. Bartha I
    23. Bianchi S
    24. Silacci-Fregni C
    25. Bassi J
    26. Marzi R
    27. Vetti E
    28. Cassotta A
    29. Ceschi A
    30. Ferrari P
    31. Cippà PE
    32. Giannini O
    33. Ceruti S
    34. Garzoni C
    35. Riva A
    36. Benigni F
    37. Cameroni E
    38. Piccoli L
    39. Pizzuto MS
    40. Smithey M
    41. Hong D
    42. Telenti A
    43. Lempp FA
    44. Neyts J
    45. Havenar-Daughton C
    46. Lanzavecchia A
    47. Sallusto F
    48. Snell G
    49. Virgin HW
    50. Beltramello M
    51. Corti D
    52. Veesler D

    (2021) Broad betacoronavirus neutralization by a stem helix-specific human antibody

    Science 373:1109–1116.

    https://doi.org/10.1126/science.abj3321

    • PubMed
    • Google Scholar
51. 1. Planas D
    2. Veyer D
    3. Baidaliuk A
    4. Staropoli I
    5. Guivel-Benhassine F
    6. Rajah MM
    7. Planchais C
    8. Porrot F
    9. Robillard N
    10. Puech J
    11. Prot M
    12. Gallais F
    13. Gantner P
    14. Velay A
    15. Le Guen J
    16. Kassis-Chikhani N
    17. Edriss D
    18. Belec L
    19. Seve A
    20. Courtellemont L
    21. Péré H
    22. Hocqueloux L
    23. Fafi-Kremer S
    24. Prazuck T
    25. Mouquet H
    26. Bruel T
    27. Simon-Lorière E
    28. Rey FA
    29. Schwartz O

    (2021) Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization

    Nature 596:276–280.

    https://doi.org/10.1038/s41586-021-03777-9

    • PubMed
    • Google Scholar
52. 1. Polack FP
    2. Thomas SJ
    3. Kitchin N
    4. Absalon J
    5. Gurtman A
    6. Lockhart S
    7. Perez JL
    8. Pérez Marc G
    9. Moreira ED
    10. Zerbini C
    11. Bailey R
    12. Swanson KA
    13. Roychoudhury S
    14. Koury K
    15. Li P
    16. Kalina WV
    17. Cooper D
    18. Frenck RW Jr
    19. Hammitt LL
    20. Türeci Ö
    21. Nell H
    22. Schaefer A
    23. Ünal S
    24. Tresnan DB
    25. Mather S
    26. Dormitzer PR
    27. Şahin U
    28. Jansen KU
    29. Gruber WC
    30. C4591001 Clinical Trial Group

    (2020) Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine

    The New England Journal of Medicine 383:2603–2615.

    https://doi.org/10.1056/NEJMoa2034577

    • PubMed
    • Google Scholar
53. 1. Punjani A
    2. Rubinstein JL
    3. Fleet DJ
    4. Brubaker MA

    (2017) cryoSPARC: Algorithms for rapid unsupervised cryo-EM structure determination

    Nature Methods 14:290–296.

    https://doi.org/10.1038/nmeth.4169

    • PubMed
    • Google Scholar
54. 1. Robbiani DF
    2. Gaebler C
    3. Muecksch F
    4. Lorenzi JCC
    5. Wang Z
    6. Cho A
    7. Agudelo M
    8. Barnes CO
    9. Gazumyan A
    10. Finkin S
    11. Hägglöf T
    12. Oliveira TY
    13. Viant C
    14. Hurley A
    15. Hoffmann HH
    16. Millard KG
    17. Kost RG
    18. Cipolla M
    19. Gordon K
    20. Bianchini F
    21. Chen ST
    22. Ramos V
    23. Patel R
    24. Dizon J
    25. Shimeliovich I
    26. Mendoza P
    27. Hartweger H
    28. Nogueira L
    29. Pack M
    30. Horowitz J
    31. Schmidt F
    32. Weisblum Y
    33. Michailidis E
    34. Ashbrook AW
    35. Waltari E
    36. Pak JE
    37. Huey-Tubman KE
    38. Koranda N
    39. Hoffman PR
    40. West AP Jr
    41. Rice CM
    42. Hatziioannou T
    43. Bjorkman PJ
    44. Bieniasz PD
    45. Caskey M
    46. Nussenzweig MC

    (2020) Convergent antibody responses to SARS-CoV-2 in convalescent individuals

    Nature 584:437–442.

    https://doi.org/10.1038/s41586-020-2456-9

    • PubMed
    • Google Scholar
55. 1. Rydyznski Moderbacher C
    2. Ramirez SI
    3. Dan JM
    4. Grifoni A
    5. Hastie KM
    6. Weiskopf D
    7. Belanger S
    8. Abbott RK
    9. Kim C
    10. Choi J
    11. Kato Y
    12. Crotty EG
    13. Kim C
    14. Rawlings SA
    15. Mateus J
    16. Tse LPV
    17. Frazier A
    18. Baric R
    19. Peters B
    20. Greenbaum J
    21. Saphire EO
    22. Smith DM
    23. Sette A
    24. Crotty S

    (2020) Antigen-specific adaptive immunity to SARS-CoV-2 in acute COVID-19 and associations with age and disease severity

    Cell 183:996–1012.

    https://doi.org/10.1016/j.cell.2020.09.038

    • PubMed
    • Google Scholar
56. 1. Sanders RW
    2. Derking R
    3. Cupo A
    4. Julien JP
    5. Yasmeen A
    6. de Val N
    7. Kim HJ
    8. Blattner C
    9. de la Peña AT
    10. Korzun J
    11. Golabek M
    12. de los Reyes K
    13. Ketas TJ
    14. van Gils MJ
    15. King CR
    16. Wilson IA
    17. Ward AB
    18. Klasse PJ
    19. Moore JP

    (2013) A next-generation cleaved, soluble HIV-1 Env Trimer, BG505 SOSIP.664 gp140, expresses multiple epitopes for broadly neutralizing but not non-neutralizing antibodies

    PLOS Pathogens 9:e1003618.

    https://doi.org/10.1371/journal.ppat.1003618

    • Google Scholar
57. 1. Saphire EO
    2. Parren PW
    3. Pantophlet R
    4. Zwick MB
    5. Morris GM
    6. Rudd PM
    7. Dwek RA
    8. Stanfield RL
    9. Burton DR
    10. Wilson IA

    (2001) Crystal structure of a neutralizing human IGG against HIV-1: A template for vaccine design

    Science 293:1155–1159.

    https://doi.org/10.1126/science.1061692

    • PubMed
    • Google Scholar
58. 1. Scheaffer SM
    2. Lee D
    3. Whitener B
    4. Ying B
    5. Wu K
    6. Liang CY
    7. Jani H
    8. Martin P
    9. Amato NJ
    10. Avena LE
    11. Berrueta DM
    12. Schmidt SD
    13. O’Dell S
    14. Nasir A
    15. Chuang GY
    16. Stewart-Jones G
    17. Koup RA
    18. Doria-Rose NA
    19. Carfi A
    20. Elbashir SM
    21. Thackray LB
    22. Edwards DK
    23. Diamond MS

    (2023) Bivalent SARS-CoV-2 mRNA vaccines increase breadth of neutralization and protect against the BA.5 Omicron variant in mice

    Nature Medicine 29:247–257.

    https://doi.org/10.1038/s41591-022-02092-8

    • PubMed
    • Google Scholar
59. 1. Song S
    2. Madewell ZJ
    3. Liu M
    4. Miao Y
    5. Xiang S
    6. Huo Y
    7. Sarkar S
    8. Chowdhury A
    9. Longini IM Jr
    10. Yang Y

    (2024) A systematic review and meta-analysis on the effectiveness of bivalent mRNA booster vaccines against Omicron variants

    Vaccine 42:3389–3396.

    https://doi.org/10.1016/j.vaccine.2024.04.049

    • PubMed
    • Google Scholar
60. 1. Starr TN
    2. Greaney AJ
    3. Hilton SK
    4. Ellis D
    5. Crawford KHD
    6. Dingens AS
    7. Navarro MJ
    8. Bowen JE
    9. Tortorici MA
    10. Walls AC
    11. King NP
    12. Veesler D
    13. Bloom JD

    (2020) Deep mutational scanning of SARS-CoV-2 receptor binding domain reveals constraints on folding and ACE2 binding

    Cell 182:1295–1310.

    https://doi.org/10.1016/j.cell.2020.08.012

    • PubMed
    • Google Scholar
61. 1. Starr TN
    2. Greaney AJ
    3. Hannon WW
    4. Loes AN
    5. Hauser K
    6. Dillen JR
    7. Ferri E
    8. Farrell AG
    9. Dadonaite B
    10. McCallum M
    11. Matreyek KA
    12. Corti D
    13. Veesler D
    14. Snell G
    15. Bloom JD

    (2022) Shifting mutational constraints in the SARS-CoV-2 receptor-binding domain during viral evolution

    Science 377:420–424.

    https://doi.org/10.1126/science.abo7896

    • Google Scholar
62. 1. Tan CY
    2. Chiew CJ
    3. Pang D
    4. Lee VJ
    5. Ong B
    6. Wang LF
    7. Ren EC
    8. Lye DC
    9. Tan KB

    (2023) Effectiveness of bivalent mRNA vaccines against medically attended symptomatic SARS-CoV-2 infection and COVID-19-related hospital admission among SARS-CoV-2-naive and previously infected individuals: a retrospective cohort study

    The Lancet Infectious Diseases 23:1343–1348.

    https://doi.org/10.1016/S1473-3099(23)00373-0

    • Google Scholar
63. 1. Taylor AL
    2. Starr TN

    (2023) Deep mutational scans of XBB.1.5 and BQ.1.1 reveal ongoing epistatic drift during SARS-CoV-2 evolution

    PLOS Pathogens 19:e1011901.

    https://doi.org/10.1371/journal.ppat.1011901

    • PubMed
    • Google Scholar
64. 1. Tseng HF
    2. Ackerson BK
    3. Luo Y
    4. Sy LS
    5. Talarico CA
    6. Tian Y
    7. Bruxvoort KJ
    8. Tubert JE
    9. Florea A
    10. Ku JH
    11. Lee GS
    12. Choi SK
    13. Takhar HS
    14. Aragones M
    15. Qian L

    (2022) Effectiveness of mRNA-1273 against SARS-CoV-2 Omicron and delta variants

    Nature Medicine 28:1063–1071.

    https://doi.org/10.1038/s41591-022-01753-y

    • PubMed
    • Google Scholar
65. 1. Walls AC
    2. Park YJ
    3. Tortorici MA
    4. Wall A
    5. McGuire AT
    6. Veesler D

    (2020) Structure, function, and antigenicity of the SARS-CoV-2 spike glycoprotein

    Cell 181:281–292.

    https://doi.org/10.1016/j.cell.2020.02.058

    • PubMed
    • Google Scholar
66. 1. Wang Z
    2. Muecksch F
    3. Cho A
    4. Gaebler C
    5. Hoffmann HH
    6. Ramos V
    7. Zong S
    8. Cipolla M
    9. Johnson B
    10. Schmidt F
    11. DaSilva J
    12. Bednarski E
    13. Ben Tanfous T
    14. Raspe R
    15. Yao K
    16. Lee YE
    17. Chen T
    18. Turroja M
    19. Milard KG
    20. Dizon J
    21. Kaczynska A
    22. Gazumyan A
    23. Oliveira TY
    24. Rice CM
    25. Caskey M
    26. Bieniasz PD
    27. Hatziioannou T
    28. Barnes CO
    29. Nussenzweig MC

    (2022) Analysis of memory B cells identifies conserved neutralizing epitopes on the N-terminal domain of variant SARS-Cov-2 spike proteins

    Immunity 55:998–1012.

    https://doi.org/10.1016/j.immuni.2022.04.003

    • PubMed
    • Google Scholar
67. 1. Wang Q
    2. Bowen A
    3. Tam AR
    4. Valdez R
    5. Stoneman E
    6. Mellis IA
    7. Gordon A
    8. Liu L
    9. Ho DD

    (2023a) SARS-CoV-2 neutralising antibodies after bivalent versus monovalent booster

    The Lancet. Infectious Diseases 23:527–528.

    https://doi.org/10.1016/S1473-3099(23)00181-0

    • PubMed
    • Google Scholar
68. 1. Wang Q
    2. Guo Y
    3. Tam AR
    4. Valdez R
    5. Gordon A
    6. Liu L
    7. Ho DD

    (2023b) Deep immunological imprinting due to the ancestral spike in the current bivalent COVID-19 vaccine

    Cell Reports Medicine 4:101258.

    https://doi.org/10.1016/j.xcrm.2023.101258

    • Google Scholar
69. 1. Wang Q
    2. Iketani S
    3. Li Z
    4. Liu L
    5. Guo Y
    6. Huang Y
    7. Bowen AD
    8. Liu M
    9. Wang M
    10. Yu J
    11. Valdez R
    12. Lauring AS
    13. Sheng Z
    14. Wang HH
    15. Gordon A
    16. Liu L
    17. Ho DD

    (2023c) Alarming antibody evasion properties of rising SARS-CoV-2 BQ and XBB subvariants

    Cell 186:279–286.

    https://doi.org/10.1016/j.cell.2022.12.018

    • PubMed
    • Google Scholar
70. 1. West AP
    2. Scharf L
    3. Horwitz J
    4. Klein F
    5. Nussenzweig MC
    6. Bjorkman PJ

    (2013) Computational analysis of anti–HIV-1 antibody neutralization panel data to identify potential functional epitope residues

    PNAS 110:10598–10603.

    https://doi.org/10.1073/pnas.1309215110

    • Google Scholar
71. Website

    1. WHO

    (2021) Classification of Omicron (B.1.1.529): SARS‐CoV‐2 variant of concern

    Accessed November 26, 2021.

    https://www.who.int/news/item/26-11-2021-classification-of-omicron-(b.1.1.529)-sars-cov-2-variant-of-concern
72. 1. Wrapp D
    2. Wang N
    3. Corbett KS
    4. Goldsmith JA
    5. Hsieh CL
    6. Abiona O
    7. Graham BS
    8. McLellan JS

    (2020) Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation

    Science 367:1260–1263.

    https://doi.org/10.1126/science.abb2507

    • Google Scholar
73. 1. Ying B
    2. Scheaffer SM
    3. Whitener B
    4. Liang CY
    5. Dmytrenko O
    6. Mackin S
    7. Wu K
    8. Lee D
    9. Avena LE
    10. Chong Z
    11. Case JB
    12. Ma L
    13. Kim TTM
    14. Sein CE
    15. Woods A
    16. Berrueta DM
    17. Chang GY
    18. Stewart-Jones G
    19. Renzi I
    20. Lai YT
    21. Malinowski A
    22. Carfi A
    23. Elbashir SM
    24. Edwards DK
    25. Thackray LB
    26. Diamond MS

    (2022) Boosting with variant-matched or historical mRNA vaccines protects against Omicron infection in mice

    Cell 185:1572–1587.

    https://doi.org/10.1016/j.cell.2022.03.037

    • Google Scholar
74. 1. Zhang Z
    2. Mateus J
    3. Coelho CH
    4. Dan JM
    5. Moderbacher CR
    6. Gálvez RI
    7. Cortes FH
    8. Grifoni A
    9. Tarke A
    10. Chang J
    11. Escarrega EA
    12. Kim C
    13. Goodwin B
    14. Bloom NI
    15. Frazier A
    16. Weiskopf D
    17. Sette A
    18. Crotty S

    (2022) Humoral and cellular immune memory to four COVID-19 vaccines

    Cell 185:2434–2451.

    https://doi.org/10.1016/j.cell.2022.05.022

    • PubMed
    • Google Scholar
75. 1. Zheng C
    2. Shao W
    3. Chen X
    4. Zhang B
    5. Wang G
    6. Zhang W

    (2022) Real-world effectiveness of COVID-19 vaccines: a literature review and meta-analysis

    International Journal of Infectious Diseases 114:252–260.

    https://doi.org/10.1016/j.ijid.2021.11.009

    • PubMed
    • Google Scholar

Author details

1. Chengcheng Fan

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Contribution

   Conceptualization, Data curation, Formal analysis, Validation, Investigation, Visualization, Methodology, Writing – original draft, Writing – review and editing

   Contributed equally with

   Alexander A Cohen and Kim-Marie A Dam

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0003-4213-5758

2. Alexander A Cohen

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Contribution

   Conceptualization, Data curation, Formal analysis, Supervision, Validation, Investigation, Visualization, Methodology, Writing – original draft, Writing – review and editing

   Contributed equally with

   Chengcheng Fan and Kim-Marie A Dam

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0002-2818-656X

3. Kim-Marie A Dam

   Gladstone Institutes, San Francisco, United States

   Contribution

   Conceptualization, Data curation, Formal analysis, Validation, Investigation, Visualization, Methodology, Writing – original draft, Writing – review and editing

   Contributed equally with

   Chengcheng Fan and Alexander A Cohen

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0002-1416-4757

4. Annie V Rorick

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Present address

   Department of Biochemistry, University of Washington, Seattle, United States

   Contribution

   Data curation, Formal analysis, Investigation, Methodology

   Competing interests

   No competing interests declared

5. Ange-Célia I Priso Fils

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Contribution

   Data curation, Formal analysis, Investigation, Methodology

   Competing interests

   No competing interests declared

6. Zhi Yang

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Present address

   Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

   Contribution

   Data curation, Formal analysis, Validation, Investigation, Methodology

   Competing interests

   No competing interests declared

   "This ORCID iD identifies the author of this article:" 0000-0001-8680-3784

7. Priyanthi NP Gnanapragasam

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Contribution

   Data curation, Formal analysis, Investigation, Methodology

   Competing interests

   No competing interests declared

8. Luisa N Segovia

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Contribution

   Data curation, Investigation, Methodology

   Competing interests

   No competing interests declared

9. Kathryn E Huey-Tubman

   Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

   Contribution

   Data curation, Formal analysis, Investigation, Methodology

   Competing interests

   No competing interests declared

10. Woohyun J Moon

    Acuitas Therapeutics, Vancouver, Canada

    Contribution

    Resources, Methodology

    Competing interests

    employee of Acuitas Therapeutics, a company developing lipid nanoparticle delivery technology

11. Paulo JC Lin

    Acuitas Therapeutics, Vancouver, Canada

    Contribution

    Resources, Methodology, Writing – review and editing

    Competing interests

    employee of Acuitas Therapeutics, a company developing lipid nanoparticle delivery technology; holds equity in Acuitas Therapeutics

12. Pamela J Bjorkman

    Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States

    Contribution

    Conceptualization, Resources, Formal analysis, Supervision, Funding acquisition, Investigation, Visualization, Methodology, Writing – original draft, Project administration, Writing – review and editing

    For correspondence

    bjorkman@caltech.edu

    Competing interests

    inventor on a US patent application filed by the California Institute of Technology that covers the EABR technology described in this work; is a scientific advisor for Vaccine Company, Inc

    "This ORCID iD identifies the author of this article:" 0000-0002-2277-3990

13. Magnus AG Hoffmann

    1. Gladstone Institutes, San Francisco, United States
    2. Department of Medicine, University of California, San Francisco, San Francisco, United States

    Contribution

    Conceptualization, Resources, Data curation, Formal analysis, Supervision, Funding acquisition, Validation, Investigation, Methodology, Writing – original draft, Project administration, Writing – review and editing

    For correspondence

    magnus.hoffmann@gladstone.ucsf.edu

    Competing interests

    inventor on a US patent application filed by the California Institute of Technology that covers the EABR technology described in this work; is a scientific consultant for Vaccine Company, Inc

    "This ORCID iD identifies the author of this article:" 0000-0003-4923-9568

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