The effect of variation of individual infectiousness on SARS-CoV-2 transmission in households
Figures

Summary of statistics for 17 identified studies.
Figure shows the average number of contacts and standard deviation (SD) of number of contact, SD of number of secondary cases per index cases (), and secondary attack rate (SAR) for 17 identified studies.

Modeling results of household transmission dynamics and infectiousness variation.
Figure shows the estimates of infectiousness variation (), the estimated probability of infection from community and estimated probability of infection from households, and the reduction in deviance information criteriion (DIC) compared with the model without infectiousness variation. Models are fitted separately to 14 household transmission studies.

Estimate distribution of relative infectiousness based on the pooled estimate.
Red line indicates the estimated distribution and the gray lines indicate the associated uncertainty. Black dashed line indicates average infectiousness (relative infectiousness equal to 1), while the purple and blue dashed lines indicate top 20% and 10% infectiousness, respectively.

Relationship between infectiousness variation and statistic.
In each panel, numbers represent the observed corresponding relationship for the identified studies. Panels A and B show the relationship between infectiousness variation () and secondary attack rate (SAR) and standard deviation (SD) of number of secondary cases per index cases (). In the bottom, numbers in bracket indicate the number of household contacts in corresponding studies.

Correlation plots for the posterior distribution of model parameters in Lyngse et al., Carazo et al., Laxminarayan et al., and Dattner et al.
Tables
Summary of characteristic of identified studies.
Author (year) | Location | Study period | Case ascertainment method | Test coverage of identified contacts | SARS-COV-2 variant | Public health and social measures |
---|---|---|---|---|---|---|
Lyngse et al., 2022 | Denmark | February 2020 to August 2020 | Index: RT-PCR Secondary: RT-PCR | All contacts were tested | Ancestral strains | Lockdown |
Carazo et al., 2022 | Canada | March 2020 to June 2020 | Index: RT-PCR Secondary: Symptom-based | NA | Ancestral strains | Handwashing, mask-wearing, and physical distancing |
Laxminarayan et al., 2020 | India | March 2020 to July 2020 | Index: RT-PCR Secondary: RT-PCR | All contacts were tested | Ancestral strains | Lockdown, social distancing, contact tracing |
Dattner et al., 2021 | Israel | March 2020 to June 2020 | Index: RT-PCR and Serology Secondary: RT-PCR and Serology | All contacts were tested | Ancestral strains | Lockdown |
Layan et al., 2022 | Israel | December 2020 to April 2021 | Index: RT-PCR Secondary: RT-PCR | All contacts were tested | Ancestral strains, alpha | Vaccination |
Hart et al., 2022 | UK | March 2020 to November 2020 | Index: RT-PCR Secondary: RT-PCR and antibody test | All contacts were tested | Ancestral strains | Isolation |
Hubiche et al., 2021 | Canada | April 2020 to June 2020 | Index: Symptom-based and RT-PCR and serology Secondary: Symptom-based and RT-PCR and serology | NA | Ancestral strains | Closure of school |
Wilkinson et al., 2021 | Manitoba, Canada | Mid-January 2020 to late March 2020 | Index: NAAT assay Secondary: NAAT assay | Only symptomatic contacts were tested | Ancestral strains | Isolation and contact tracing |
Tsang et al., 2022 | Shandong Province, China | January 2020 to May 2020 | Index: RT-PCR Secondary: RT-PCR | All contacts were tested | Ancestral strains | Isolation, mask-waring, social distancing |
Reukers et al., 2021 | Netherlands | March 2020 to May 2020 | Index: RT-PCR Secondary: RT-PCR | NA | Ancestral strains | Social distancing |
Han et al., 2022 | Netherlands | March 2020 to April 2020 | Index: RT-PCR and serology Secondary: RT-PCR and serology | All contacts were tested | Ancestral strains | Social distancing, self-quarantine and self-isolation orders, closure of schools, bars and restaurants, and urging people to work from home |
MΓ©ndez-EchevarrΓa et al., 2021 | Madrid, Spain | March 2020 to May 2020 | Index: RT-PCR and serology Secondary: RT-PCR and serology | All contacts were tested | Ancestral strains | Lockdown |
Dutta et al., 2020 | Rajasthan, India | May 2020 to July 2020 | Index: RTβPCR Secondary: RTβPCR | All contacts were tested | Ancestral strains | Lockdown and stay-at-home orders, physical distancing |
Koureas et al., 2021 | Greece | April 2020 to June 2020 | Index: RT-PCR Secondary: RT-PCR | All contacts were tested | Ancestral strains | Quarantine, screening, movement restrictions and gathering prohibition, isolation |
Bernardes-Souza et al., 2021; MΓ©ndez-EchevarrΓa et al., 2021 | Brazil | May 2020 to June 2020 | Index: Serology and RT-PCR Secondary: Serology | All contacts were tested | Ancestral strains | Lockdown, gathering restrictions and face mask mandates |
Posfay-Barbe et al., 2020 | Switzerland | March 2020 to April 2020 | Index: RT-PCR Secondary: RT-PCR | NA | Ancestral strains | Closure of schools, daycares, restaurants, bars, and shops, social distancing |
Hsu et al., 2021 | Taiwan, China | January 2020 to February 2021 | Index: RT-PCR Secondary: RT-PCR | Only symptomatic contacts were tested | Ancestral strains, alpha | Mask-wearing, hand washing, and social distancing |
Summary of model estimates.
Article | Estimates of infectiousness variation | Estimates of probability of infection from community (10β2) | Estimates of probability of infection from household | Relationship between transmission and number of contacts ( |
---|---|---|---|---|
Lyngse et al. | 1.48 (1.29, 1.7) | 0.06 (0, 0.16) | 0.1 (0.08, 0.12) | 0.72 (0.59, 0.89) |
Carazo et al. | 1.41 (1.19, 1.72) | 0.2 (0.01, 0.43) | 0.3 (0.24, 0.34) | 0.75 (0.62, 0.93) |
Laxminarayan et al. | 2.44 (1.98, 3.23) | 0.03 (0, 0.11) | 0.04 (0.01, 0.07) | 0.92 (0.69, 1) |
Dattner et al. | 1.12 (0.65, 1.69) | 0.63 (0.12, 1.06) | 0.31 (0.19, 0.42) | 0.65 (0.45, 0.91) |
Layan et al. | 1.12 (0.74, 1.76) | 0.3 (0.02, 0.96) | 0.26 (0.15, 0.39) | 0.2 (0.01, 0.6) |
Hart et al. | 0.35 (0.11, 0.96) | 0.74 (0.05, 2.12) | 0.51 (0.32, 0.65) | 0.72 (0.32, 0.98) |
Hubiche et al. | 1.03 (0.45, 2.68) | 1.24 (0.14, 2.48) | 0.32 (0.06, 0.57) | 0.67 (0.13, 0.98) |
Wilkinson et al. | 1.05 (0.12, 3.51) | 0.32 (0.02, 0.91) | 0.07 (0, 0.18) | 0.43 (0.02, 0.97) |
Tsang et al. | 2.83 (1.48, 4.73) | 0.45 (0.05, 1.03) | 0.06 (0, 0.26) | 0.66 (0.06, 0.99) |
Reukers et al. | 1.79 (0.72, 4.5) | 1.53 (0.18, 2.93) | 0.22 (0.01, 0.6) | 0.67 (0.07, 0.98) |
Han et al. | 1.71 (0.51, 4.13) | 1.67 (0.19, 2.99) | 0.21 (0.02, 0.61) | 0.69 (0.07, 0.99) |
MΓ©ndez-EchevarrΓa et al. | 0.51 (0.13, 1.7) | 0.91 (0.05, 2.53) | 0.28 (0.06, 0.52) | 0.57 (0.04, 0.98) |
Dutta et al. | 1.53 (0.5, 4.2) | 1.1 (0.12, 2.26) | 0.24 (0.01, 0.63) | 0.78 (0.15, 0.99) |
Koureas et al. | 1.88 (0.6, 3.66) | 0.84 (0.1, 1.76) | 0.13 (0.01, 0.42) | 0.44 (0.02, 0.96) |
Model adequacy check for Lyngse et al.
Each element of the table has the format observed frequency β expected (posterior mean) frequency (95% credible interval).
Number of household contacts | Number of infected household contacts | |||||
---|---|---|---|---|---|---|
0 | 1 | 2 | 3 | 4 | 5 | |
1 | 2366β2377 (2319, 2433) | 569β558 (502, 616) | NA | NA | NA | NA |
2 | 1117β1105 (1070, 1138) | 227β227 (198, 259) | 77β88 (69, 109) | NA | NA | NA |
3 | 1135β1118 (1077, 1156) | 214β235 (203, 267) | 89β86 (67, 106) | 41β41 (27, 56) | NA | NA |
4 | 521β528 (501, 555) | 119β115 (94, 137) | 40β42 (30, 56) | 25β19 (11, 30) | 11β10 (4, 18) | NA |
5 | 161β167 (152, 181) | 42β38 (27, 50) | 14β14 (7, 22) | 7β7 (2, 12) | 7β3 (0, 8) | 0β2 (0, 5) |
Model adequacy check for Carazo et al.
Each element of the table has the format observed frequency β expected (posterior mean) frequency (95% credible interval).
Number of household contacts | Number of infected household contacts | |||||
---|---|---|---|---|---|---|
0 | 1 | 2 | 3 | 4 | 5 | |
1 | 803β814 (765, 862) | 532β521 (473, 570) | NA | NA | NA | NA |
2 | 476β454 (423, 485) | 179β186 (160, 212) | 154β169 (144, 195) | NA | NA | NA |
3 | 518β520 (483, 557) | 201β202 (175, 232) | 132β130 (107, 155) | 133β131 (106, 158) | NA | NA |
4 | 217β221 (197, 245) | 85β87 (70, 106) | 52β52 (39, 67) | 43β39 (27, 52) | 45β41 (28, 56) | NA |
5 | 76β74 (61, 88) | 30β30 (20, 41) | 20β18 (10, 26) | 13β12 (6, 20) | 7β10 (5, 17) | 10β11 (5, 18) |
Model adequacy check for Laxminarayan et al.
Each element of the table has the format observed frequency β expected (posterior mean) frequency (95% credible interval).
Number of household contacts | Number of infected household contacts | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
1 | 124β134 (122, 144) | 37β27 (17, 39) | NA | NA | NA | NA | NA | NA | NA | NA |
2 | 135β137 (125, 147) | 12β18 (10, 27) | 20β12 (6, 20) | NA | NA | NA | NA | NA | NA | NA |
3 | 188β176 (163, 188) | 13β22 (13, 33) | 11β9 (4, 16) | 5β9 (4, 17) | NA | NA | NA | NA | NA | NA |
4 | 127β118 (108, 128) | 11β15 (8, 23) | 5β5 (1, 11) | 3β3 (0, 7) | 1β4 (1, 10) | NA | NA | NA | NA | NA |
5 | 75β76 (67, 84) | 12β10 (4, 16) | 3β3 (0, 8) | 1β2 (0, 5) | 1β1 (0, 4) | 3β2 (0, 6) | NA | NA | NA | NA |
6 | 41β40 (34, 46) | 7β5 (1, 10) | 2β2 (0, 5) | 0β1 (0, 3) | 0β0 (0, 3) | 0β0 (0, 2) | 1β1 (0, 3) | NA | NA | NA |
7 | 32β31 (25, 36) | 3β4 (1, 9) | 2β1 (0, 4) | 1β1 (0, 3) | 1β0 (0, 2) | 0β0 (0, 2) | 0β0 (0, 2) | 0β0 (0, 3) | NA | NA |
8 | 10β13 (10, 16) | 2β2 (0, 5) | 3β0 (0, 2) | 1β0 (0, 2) | 0β0 (0, 1) | 1β0 (0, 1) | 0β0 (0, 1) | 0β0 (0, 1) | 0β0 (0, 1) | NA |
9 | 14β16 (12, 20) | 2β2 (0, 6) | 1β1 (0, 3) | 2β0 (0, 2) | 1β0 (0, 2) | 0β0 (0, 1) | 0β0 (0, 1) | 0β0 (0, 1) | 0β0 (0, 1) | 1β0 (0, 2) |
Model adequacy check for Dattner et al.
Each element of the table has the format observed frequency β expected (posterior mean) frequency (95% credible interval).
Number of household contacts | Number of infected household contacts | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
1 | 85β93 (77, 108) | 73β65 (50, 81) | NA | NA | NA | NA | NA | NA | NA | NA |
2 | 46β42 (32, 52) | 21β25 (17, 34) | 19β19 (11, 28) | NA | NA | NA | NA | NA | NA | NA |
3 | 38β29 (21, 38) | 13β18 (11, 25) | 9β12 (6, 19) | 8β9 (4, 15) | NA | NA | NA | NA | NA | NA |
4 | 24β24 (16, 32) | 19β15 (9, 23) | 11β10 (5, 17) | 8β7 (3, 13) | 1β5 (1, 11) | NA | NA | NA | NA | NA |
5 | 25β21 (14, 30) | 15β15 (9, 22) | 12β10 (5, 17) | 7β7 (3, 13) | 3β5 (2, 10) | 2β4 (1, 9) | NA | NA | NA | NA |
6 | 13β16 (9, 23) | 19β12 (6, 18) | 3β8 (3, 14) | 5β6 (2, 11) | 3β5 (1, 9) | 5β3 (0, 7) | 5β2 (0, 6) | NA | NA | NA |
7 | 5β9 (4, 15) | 6β7 (3, 13) | 5β5 (2, 10) | 7β4 (1, 8) | 4β3 (0, 7) | 4β2 (0, 6) | 4β2 (0, 5) | 0β1 (0, 4) | NA | NA |
8 | 10β8 (3, 14) | 7β7 (3, 12) | 3β5 (1, 10) | 4β4 (1, 8) | 0β3 (0, 7) | 3β2 (0, 6) | 3β2 (0, 5) | 4β1 (0, 4) | 0β1 (0, 4) | NA |
9 | 6β6 (2, 12) | 3β6 (2, 10) | 4β4 (1, 9) | 6β3 (0, 7) | 4β3 (0, 6) | 1β2 (0, 5) | 2β2 (0, 5) | 2β1 (0, 4) | 2β1 (0, 3) | 0β0 (0, 3) |
Comparison of model estimates from 100k Markov chain Monte Carlo (MCMC) iterations and 500k MCMC iterations.
Article | Number of MCMC iterations | Estimates of infectiousness variation | Estimates of probability of infection from community (10β2) | Estimates of probability of infection from household | Relationship between transmission and number of contacts ( |
---|---|---|---|---|---|
Lyngse et al. | 100,000 | 1.48 (1.29, 1.7) | 0.06 (0, 0.16) | 0.11 (0.08, 0.13) | 0.72 (0.59, 0.89) |
500,000 | 1.49 (1.29, 1.84) | 0.07 (0, 0.2) | 0.1 (0.07, 0.13) | 0.74 (0.6, 0.92) | |
Carazo et al. | 100,000 | 1.41 (1.19, 1.72) | 0.2 (0.01, 0.43) | 0.35 (0.27, 0.42) | 0.75 (0.62, 0.93) |
500,000 | 1.44 (1.19, 1.78) | 0.21 (0.02, 0.46) | 0.34 (0.26, 0.41) | 0.77 (0.62, 0.95) | |
Laxminarayan et al. | 100,000 | 2.44 (1.98, 3.23) | 0.03 (0, 0.11) | 0.04 (0.01, 0.08) | 0.92 (0.69, 1) |
500,000 | 2.47 (1.99, 3.23) | 0.03 (0, 0.11) | 0.04 (0.01, 0.07) | 0.92 (0.67, 1) | |
Dattner et al. | 100,000 | 1.12 (0.65, 1.69) | 0.63 (0.12, 1.06) | 0.37 (0.21, 0.54) | 0.65 (0.45, 0.91) |
500,000 | 1.06 (0.65, 1.55) | 0.57 (0.1, 1) | 0.38 (0.24, 0.54) | 0.63 (0.43, 0.88) |
Simulation study for validating the estimates and the corresponding power.
Parameter | Simulation value | Mean estimate | Proportion covered (over 50) |
---|---|---|---|
Lyngse et al. | |||
β: Infectiousness variation | 1.48 | 1.57 | 0.94 |
β: hazard of infection from outside the household (10β2) | 0.06 | 0.12 | 0.88 |
β: hazard of infection from an infected household member | 0.11 | 0.09 | 0.92 |
relationship between number of household contacts and transmission rate | 0.72 | 0.75 | 0.96 |
Carazo et al. | |||
β: Infectiousness variation | 1.41 | 1.49 | 0.94 |
β: hazard of infection from outside the household (10β2) | 0.2 | 0.24 | 0.96 |
β: hazard of infection from an infected household member | 0.35 | 0.33 | 0.92 |
relationship between number of household contacts and transmission rate | 0.75 | 0.77 | 0.96 |
Laxminarayan et al. | |||
β: Infectiousness variation | 2.44 | 2.6 | 0.94 |
β: hazard of infection from outside the household (10β2) | 0.03 | 0.05 | 0.96 |
β: hazard of infection from an infected household member | 0.04 | 0.03 | 0.9 |
relationship between number of household contacts and transmission rate | 0.92 | 0.82 | 1 |
Dattner et al. | |||
β: Infectiousness variation | 1.12 | 1.18 | 0.92 |
β: hazard of infection from outside the household (10β2) | 0.63 | 0.69 | 0.92 |
β: hazard of infection from an infected household member | 0.37 | 0.36 | 0.96 |
relationship between number of household contacts and transmission rate | 0.65 | 0.68 | 0.98 |
A sensitivity analysis of using normal distribution (main analysis) instead of lognormal distribution (sensitivity analysis) for individual infectiousness.
Article | Model | Estimates of infectiousness variation | Estimates of probability of infection from community (10β2) | Estimates of probability of infection from household | Relationship between transmission and number of contacts ( | Difference in DIC |
---|---|---|---|---|---|---|
Lyngse et al. | Main analysis | 1.48 (1.29, 1.7) | 0.06 (0, 0.16) | 0.11 (0.08, 0.13) | 0.72 (0.59, 0.89) | |
Sensitivity analysis | 0.93 (0.84, 1.03) | 0.03 (0, 0.11) | 0.06 (0.05, 0.07) | 0.7 (0.58, 0.83) | 2821 | |
Carazo et al. | Main analysis | 1.41 (1.19, 1.72) | 0.2 (0.01, 0.43) | 0.35 (0.27, 0.42) | 0.75 (0.62, 0.93) | |
Sensitivity analysis | 1.05 (0.92, 1.21) | 0.06 (0, 0.24) | 0.18 (0.16, 0.2) | 0.71 (0.59, 0.84) | 2569 | |
Laxminarayan et al. | Main analysis | 2.44 (1.98, 3.23) | 0.03 (0, 0.11) | 0.04 (0.01, 0.08) | 0.92 (0.69, 1) | |
Sensitivity analysis | 1.31 (1.14, 1.48) | 0.02 (0, 0.08) | 0.05 (0.03, 0.06) | 0.91 (0.66, 1) | 818 | |
Dattner et al. | Main analysis | 1.12 (0.65, 1.69) | 0.63 (0.12, 1.06) | 0.37 (0.21, 0.54) | 0.65 (0.45, 0.91) | |
Sensitivity analysis | 0.66 (0.47, 0.88) | 0.3 (0.02, 0.71) | 0.18 (0.13, 0.22) | 0.56 (0.4, 0.75) | 908 |
Summary of characteristic of identified studies.
SD: standard deviation.
Article | Number of households | Number of contacts | Number of secondary cases | Mean number of contacts | SD of number of contact | Secondary attack rate (SAR) | SD of number of secondary cases () |
---|---|---|---|---|---|---|---|
Lyngse et al. | 6782 | 14,233 | 1902 | 2.1 (2.07, 2.13) | 1.17 (1.15, 1.19) | 0.13 (0.13, 0.14) | 0.6 (0.59, 0.61) |
Carazo et al. | 3727 | 8460 | 2574 | 2.27 (2.23, 2.31) | 1.19 (1.16, 1.21) | 0.3 (0.29, 0.31) | 0.97 (0.95, 0.99) |
Laxminarayan et al. | 915 | 3113 | 283 | 3.4 (3.28, 3.53) | 1.94 (1.86, 2.04) | 0.09 (0.08, 0.1) | 0.81 (0.77, 0.85) |
Dattner et al. | 591 | 2211 | 720 | 3.74 (3.54, 3.94) | 2.5 (2.36, 2.65) | 0.33 (0.31, 0.35) | 1.6 (1.51, 1.7) |
Layan et al. | 208 | 670 | 264 | 3.22 (3.01, 3.44) | 1.58 (1.45, 1.75) | 0.39 (0.36, 0.43) | 1.59 (1.45, 1.76) |
Hart et al. | 172 | 433 | 194 | 2.52 (2.34, 2.69) | 1.16 (1.05, 1.29) | 0.45 (0.4, 0.5) | 1.11 (1, 1.24) |
Hubiche et al. | 103 | 291 | 119 | 2.83 (2.6, 3.05) | 1.18 (1.04, 1.37) | 0.41 (0.35, 0.47) | 1.14 (1, 1.32) |
Wilkinson et al. | 95 | 220 | 26 | 2.32 (2.02, 2.61) | 1.47 (1.28, 1.71) | 0.12 (0.08, 0.17) | 0.66 (0.58, 0.77) |
Tsang et al. | 47 | 189 | 38 | 4.02 (3.39, 4.66) | 2.22 (1.85, 2.79) | 0.2 (0.15, 0.27) | 1.31 (1.09, 1.65) |
Reukers et al. | 55 | 187 | 78 | 3.4 (3.11, 3.69) | 1.1 (0.93, 1.35) | 0.42 (0.35, 0.49) | 1.33 (1.12, 1.64) |
Han et al. | 55 | 185 | 78 | 3.36 (3.08, 3.65) | 1.08 (0.91, 1.33) | 0.42 (0.35, 0.5) | 1.27 (1.07, 1.57) |
MΓ©ndez-EchevarrΓa et al. | 63 | 174 | 57 | 2.76 (2.57, 2.95) | 0.78 (0.66, 0.94) | 0.33 (0.26, 0.4) | 0.96 (0.82, 1.17) |
Dutta et al. | 32 | 170 | 55 | 5.31 (4.52, 6.1) | 2.28 (1.83, 3.03) | 0.32 (0.25, 0.4) | 1.59 (1.28, 2.12) |
Koureas et al. | 32 | 153 | 50 | 4.78 (3.94, 5.62) | 2.43 (1.95, 3.23) | 0.33 (0.25, 0.41) | 2.14 (1.72, 2.84) |
Bernardes-Souza et al. | 40 | 112 | 55 | 2.8 (2.33, 3.27) | 1.51 (1.23, 1.93) | 0.49 (0.4, 0.59) | 1.48 (1.21, 1.9) |
Posfay-Barbe et al. | 39 | 111 | 46 | 2.85 (2.54, 3.16) | 0.99 (0.81, 1.27) | 0.41 (0.32, 0.51) | 0.94 (0.77, 1.21) |
Hsu et al. | 38 | 96 | 49 | 2.53 (2.12, 2.93) | 1.27 (1.03, 1.64) | 0.51 (0.41, 0.61) | 0.87 (0.71, 1.12) |
Association between infectiousness variation estimated from household transmission models, and other statistics from 17 household studies, based on meta-regression.
Statistic | Infectiousness variation (*) | Standard deviation (SD) of the distribution of number of secondary cases () | Secondary attack rate (SAR) |
---|---|---|---|
Pooled estimates | 1.33 (0.95, 1.70) | 1.19 (1.03, 1.35) | 0.35 (0.28, 0.44) |
I2 | 78.4 | 99.2 | 99.1 |
Factors | |||
Estimate | Ξ² | Ξ² | exp (Ξ²) |
Mean number of contacts | 0.31 (β0.16, 0.78) | 0.35 (0.22, 0.48) | 1.09 (0.83, 1.43) |
SD number of contacts | 0.55 (β0.12, 1.21) | 0.42 (0.15, 0.69) | 0.80 (0.51, 1.25) |
Implementation of lockdown | 0.16 (β0.61, 0.93) | β0.06 (β0.40, 0.28) | 0.69 (0.43, 1.10) |
Index cases are confirmed by PCR only | 0.48 (β0.32, 1.29) | 0.02 (β0.33, 0.38) | 1.09 (0.65, 1.85) |
Secondary cases are confirmed by PCR only | 0.78 (0.13, 1.43) | 0.03 (β0.30, 0.35) | 0.88 (0.55, 1.41) |
Only ancestral strains are circulating in study period | 0.76 (β0.03, 1.55) | 0.07 (β0.31, 0.45) | 0.75 (0.43, 1.30) |
All household contacts were tested | 0.03 (β0.87, 0.93) | 0.28 (β0.04, 0.59) | 0.96 (0.58, 1.58) |
-
*
Estimates based on results from 14 studies
Pooled estimates for duration of viral shedding for COVID-19 from 11 systematic reviews.
Study | Sampling site | Laboratory method | Pooled estimates (mean/median) | 95% CI | Range | I2 |
---|---|---|---|---|---|---|
Cevik | Upper respiratory tract | PCR | 17.0 | 15.5β18.6 | 6.0β53Β·9 | |
Cevik | Lower respiratory tract | PCR | 14.6 | 9.3β20.0 | 6.2β22.7 | 97% |
Cevik | Stool | Viral culture | 17.2 | 14.4β20.1 | 9.8β27.9 | 96.6% |
Cevik | Serum/blood | Viral culture | 16.6 | 3.6β29.7 | 10.0β23.3 | 99% |
Fontana | Respiratory sources | PCR | 18.4* | 15.5β21.3 | 5.5β53.5 | 98.87% |
Fontana | Rectal/stool | PCR | 22.1* | 14.4β29.8 | 11β33 | 95.86% |
Okita | Upper respiratory tract (nasal swab+throat swab) | PCR | 18.29 | 17.00β19.89 | 8.33β39.97 | 99% |
Okita | Sputum | PCR | 23.79 | 20.43β27.16 | 15.50β32.00 | 93% |
Okita | Blood | PCR | 14.60 | 12.16β17.05 | 11.00β17.58 | 88% |
Okita | Stool | PCR | 22.38 | 18.40β26.35 | 10.67β51.40 | 97% |
Qutub | Respiratory tract | Viral culture | 28.75/11** | 8.5β14.5 | ||
Rahmani | Respiratory tract | PCR | 27.90 | 23.27β32.52 | 7.40β132.00 | 99.1% |
Xu | Respiratory tract (symptomatic cases) | PCR | 11.1Β±5.8*** | 0β24 | ||
Xu | Gastrointestinal tract (symptomatic cases) | PCR | 23.6Β±8.8*** | 10β33 | ||
Yan | Unrestricted | PCR | 16.8 | 14.8β19.4 | 99.56% | |
Yan | Stool | PCR | 30.3 | 23.1β39.2 | 92.09% | |
Yan | Respiratory tract | PCR | 17.5 | 14.9β20.6 | 99.67% | |
Yan | Upper respiratory tract | PCR | 17.5 | 14.6β21.0 | 99.53% | |
Diaz | Stool | PCR | 22* | 19β25 | ||
Chen | (Asymptomatic infections) | 14.14* | 11.25β17.04 | 11.00β17.25 | ||
Li | Upper respiratory tract (nasopharyngeal/throat swabs) | PCR | 11.43 | 10.1β12.77 | 75.3% | |
Zhang | Stool | PCR | 21.8 | 16.4β27.1 | ||
Zhang | Respiratory tract | PCR | 14.7 | 9.9β19.5 |
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*
Median estimate, **median/grouped median, ***this study analyzed by cases, and reported mean Β± SD.
Pooled estimates for duration of viral shedding for COVID-19 in subgroups from seven systematic reviews.
Study | Sampling site (subgroups) | Laboratory method | Pooled estimates (mean/median) | 95% CI | Range | I2 |
---|---|---|---|---|---|---|
Fontana | Respiratory sources (among severely ill patients) | PCR | 19.8* | 16.2β23.5 | 11β31 | 96.42% |
Fontana | Respiratory sources (in mild-to-moderate illness) | PCR | 17.2* | 14.0β20.5 | 8β25 | 95.64% |
Okita | Upper respiratory tract (nasal swab) | PCR | 19.34 | 16.60β22.07 | 99% | |
Okita | Upper respiratory tract (throat swab) | PCR | 17.85 | 16.43β19.26 | 98% | |
Okita | Upper respiratory tract (age < 60) | PCR | 16.95 | 13.56β20.35 | 8.62β35.67 | 98% |
Okita | Upper respiratory tract (age β₯ 60) | PCR | 21.24 | 14.06β28.41 | 8.25β40.33 | 99% |
Okita | Upper respiratory tract (with comorbidities) | PCR | 20.26 | 17.60β22.92 | 9.67β34.00 | 93% |
Okita | Upper respiratory tract (without comorbidities) | PCR | 14.66 | 12.63β16.69 | 10.82β27.25 | 85% |
Okita | Upper respiratory tract (severe patients) | PCR | 20.79 | 18.03β23.55 | 14.00β38.33 | 98% |
Okita | Upper respiratory tract (nonsevere patients) | PCR | 16.36 | 14.07β18.66 | 8.00β37.33 | 99% |
Okita | Upper respiratory tract (severe patients) (for studies with mean age β₯ 40 + comorbidity > 30%) | PCR | 21.53 | 17.57β25.50 | 14.00β29.50 | 91% |
Okita | Upper respiratory tract (severe patients) (for studies with mean age β₯ 40 + comorbidity >30%) | PCR | 20.08 | 15.87β24.29 | 13.12β33.67 | 100% |
Okita | Upper respiratory tract (treated with glucocorticoid) | PCR | 19.72 | 17.92β21.52 | 13.87β33.67 | 92% |
Okita | Upper respiratory tract (treated without glucocorticoid) | PCR | 15.64 | 14.18β17.10 | 8.33β31.60 | 96% |
Okita | Upper respiratory tract (treated with glucocorticoid) (for studies with mean age: 30β60+comorbidity > 50%) | PCR | 21.98 | 16.48β27.48 | 14.25β33.67 | 94% |
Okita | Upper respiratory tract (treated without glucocorticoid) (for studies with mean age: 30β60+comorbidity > 50%) | PCR | 16.14 | 12.60β19.68 | 13.22β24.44 | 92% |
Okita | Upper respiratory tract (Asian) | PCR | 18.10 | 16.95β19.25 | 8.33β34.75 | 98% |
Okita | Upper respiratory tract (European) | PCR | 19.27 | 11.59β26.95 | 8.50β39.97 | 100% |
Okita | Upper respiratory tract (Asian) (for studies with mean age β₯ 40 + comorbidity >40%) | PCR | 20.66 | 18.18β23.14 | 12.00β32.00 | 96% |
Okita | Upper respiratory tract (European) (for studies with mean age β₯ 40 + comorbidity > 40%) | PCR | 23.68 | 10.85β36.51 | 13.00β39.97 | 100% |
Qutub | Respiratory tract (severe patients) | Viral culture | 47.5/20** | 9.0β53.0 | ||
Qutub | Respiratory tract (severe patients were not specified of excluded) | Viral culture | 10/9** | 8.0β13.0 | ||
Qutub | Respiratory tract (immunocompromised patients) | Viral culture | 54.36/20** | 9.0β85.98 | ||
Qutub | Respiratory tract (immunocompromised patients were not specified of excluded) | Viral culture | 11.67/9** | 8.2β13.3 | ||
Rahmani | Not specific (immunocompetent individuals) | PCR | 26.54 | 21.44β31.64 | 7.40β91.20 | 99.3% |
Rahmani | Not specific (immunocompromised individuals) | PCR | 36.28 | 21.93β50.63 | 15.90β132.00 | 94.2% |
Xu | Respiratory tract (asymptomatic cases) | PCR | 9.4Β±5.1*** | |||
Xu | Gastrointestinal tract (asymptomatic cases) | PCR | 16.8Β±9.8*** | |||
Yan | Unrestricted (symptomatic cases) | PCR | 19.7 | 17.2β22.7 | 99.34% | |
Yan | Unrestricted (asymptomatic cases) | PCR | 10.9 | 8.3β14.3 | 98.89% | |
Yan | Unrestricted (severe patients) | PCR | 24.3 | 18.9β31.1 | 91.88% | |
Yan | Unrestricted (nonsevere patients) | PCR | 22.8 | 16.4β32.0 | 99.81% | |
Yan | Unrestricted (females) | PCR | 19.4 | 9.5β39.4 | 93.93% | |
Yan | Unrestricted (males) | PCR | 11.9 | 8.4β16.9 | 87.83% | |
Yan | Unrestricted (adults) | PCR | 23.2 | 19.0β28.4 | 99.24% | |
Yan | Unrestricted (children) | PCR | 9.9 | 8.1β12.2 | 85.74% | |
Yan | Unrestricted (with chronic diseases) | PCR | 24.2 | 19.2β30.2 | 84.07% | |
Yan | Unrestricted (without chronic diseases) | PCR | 11.5 | 5.3β25.0 | 82.11% | |
Yan | Unrestricted (treated with corticosteroid) | PCR | 28.3 | 25.6β31.2 | 0.00% | |
Yan | Unrestricted (treated without corticosteroid) | PCR | 16.2 | 11.5β22.5 | 92.27% | |
Yan | Unrestricted (antiviral treatment) | PCR | 17.6 | 13.4β22.2 | 98.99% | |
Yan | Unrestricted (mono-antiviral treatment) | PCR | 21.2 | 15.3β29.2 | 90.04% | |
Yan | Unrestricted (multiantiviral treatment) | PCR | 20.3 | 13.7β30.3 | 99.46% | |
Chen | Unrestricted (asymptomatic infections) | PCR or serum antibody | 14.14* | 11.25β17.04 | 11.00β17.25 |
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*
Median estimate, **median/grouped median, ***this study analyzed by cases, and reported mean Β± SD.
Pooled estimates for duration of infectious period for COVID-19 in subgroups from two systematic reviews.
Study | Sampling site (subgroups) | Laboratory method | Pooled estimates | 95% CI | Range | I2 |
---|---|---|---|---|---|---|
Rahmani | Replicant competent virus isolation | Viral culture | 7.27 | 5.70β8.84 | 3.40β89.00 | 92.2% |
Wang | Not specific | Not specific | 6.25 | 5.09β7.51 | ||
Rahmani | Replicant competent virus isolation (immunocompetent individuals) | Viral culture | 6.33 | 4.92β7.75 | 3.00β13.00 | 92.4% |
Rahmani | Replicant competent virus isolation (immunocompromised individuals) | Viral culture | 29.50 | 12.46β46.53 | 13.80β89.00 | 84.8% |
Probability distributions of the incubation period and relative infectivity levels during the infectious period.
For the infectious period, day 0 corresponds to the symptom onset day. These two distributions are used to generate the infectiousness profile since infections.
Day | Incubation period | Infectious period | |
---|---|---|---|
Mean = 5 days | Day | Max = 13 days | |
1 | 0.058 | β5 | 1.0 |
2 | 0.11 | β4 | 1.0 |
3 | 0.14 | β3 | 1.0 |
4 | 0.16 | β2 | 1.0 |
5 | 0.15 | β1 | 1.0 |
6 | 0.13 | 0 | 1.0 |
7 | 0.10 | 1 | 1.0 |
8 | 0.068 | 2 | 1.0 |
9 | 0.044 | 3 | 0.8 |
10 | 0.026 | 4 | 0.6 |
11 | 0.014 | 5 | 0.4 |
12 | 0.0072 | 6 | 0.2 |
13 | 0.0034 | 7 | 0.1 |
14 | 0.0015 | 8 |
Study | Pearsonβs correlation | Shearmanβs correlation |
---|---|---|
Lyngse, et al. | 0.00 (-0.02, 0.03) | 0.00 (-0.03, 0.02) |
Carazo, et al. | 0.00 (-0.03, 0.04) | 0.00 (-0.03, 0.03) |
Laxminarayan, et al. | 0.00 (-0.07, 0.05) | -0.02 (-0.08, 0.03) |
Dattner, et al. | 0.01 (-0.07, 0.09) | 0.00 (-0.08, 0.09) |