1. Epidemiology and Global Health
  2. Microbiology and Infectious Disease
Download icon

Viral load and contact heterogeneity predict SARS-CoV-2 transmission and super-spreading events

  1. Ashish Goyal
  2. Daniel B Reeves
  3. E Fabian Cardozo-Ojeda
  4. Joshua T Schiffer  Is a corresponding author
  5. Bryan T Mayer
  1. Fred Hutchinson Cancer Research Center, United States
Research Article
  • Cited 0
  • Views 1,574
  • Annotations
Cite this article as: eLife 2021;10:e63537 doi: 10.7554/eLife.63537

Abstract

SARS-CoV-2 is difficult to contain because many transmissions occur during pre-symptomatic infection. Unlike influenza, most SARS-CoV-2 infected people do not transmit while a small percentage infect large numbers of people. We designed mathematical models which link observed viral loads with epidemiologic features of each virus, including distribution of transmissions attributed to each infected person and duration between symptom onset in the transmitter and secondarily infected person. We identify that people infected with SARS-CoV-2 or influenza can be highly contagious for less than one day, congruent with peak viral load. SARS-CoV-2 super-spreader events occur when an infected person is shedding at a very high viral load and has a high number of exposed contacts. The higher predisposition of SARS-CoV-2 towards super-spreading events cannot be attributed to additional weeks of shedding relative to influenza. Rather, a person infected with SARS-CoV-2 exposes more people within equivalent physical contact networks, likely due to aerosolization.

Article and author information

Author details

  1. Ashish Goyal

    Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
    Competing interests
    No competing interests declared.
  2. Daniel B Reeves

    Vaccine and Infectious Diseases, Fred Hutchinson Cancer Research Center, Seattle, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5684-9538
  3. E Fabian Cardozo-Ojeda

    Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
    Competing interests
    No competing interests declared.
  4. Joshua T Schiffer

    Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
    For correspondence
    jschiffe@fredhutch.org
    Competing interests
    Joshua T Schiffer, Reviewing editor, eLifeIs on the trial planning committee for a Gilead funded trial of remdesivir but is not reimbursed for this activity.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2598-1621
  5. Bryan T Mayer

    Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
    Competing interests
    No competing interests declared.

Funding

National Institute of Allergy and Infectious Diseases (R01 AI121129-05S1)

  • Joshua T Schiffer

Council of State and Territorial Epidemiologists (Inform Public Health Decision Making Funding Opportunity)

  • Joshua T Schiffer

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Lauren Childs

Publication history

  1. Received: September 28, 2020
  2. Accepted: February 22, 2021
  3. Accepted Manuscript published: February 23, 2021 (version 1)
  4. Accepted Manuscript updated: February 24, 2021 (version 2)

Copyright

© 2021, Goyal et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 1,574
    Page views
  • 177
    Downloads
  • 0
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Epidemiology and Global Health
    2. Microbiology and Infectious Disease
    Zharko Daniloski et al.
    Research Article Updated

    A novel variant of the SARS-CoV-2 virus carrying a point mutation in the Spike protein (D614G) has recently emerged and rapidly surpassed others in prevalence. This mutation is in linkage disequilibrium with an ORF1b protein variant (P314L), making it difficult to discern the functional significance of the Spike D614G mutation from population genetics alone. Here, we perform site-directed mutagenesis on wild-type human-codon-optimized Spike to introduce the D614G variant. Using multiple human cell lines, including human lung epithelial cells, we found that the lentiviral particles pseudotyped with Spike D614G are more effective at transducing cells than ones pseudotyped with wild-type Spike. The increased transduction with Spike D614G ranged from 1.3- to 2.4-fold in Caco-2 and Calu-3 cells expressing endogenous ACE2 and from 1.5- to 7.7-fold in A549ACE2 and Huh7.5ACE2 overexpressing ACE2. Furthermore, trans-complementation of SARS-CoV-2 virus with Spike D614G showed an increased infectivity in human cells. Although there is minimal difference in ACE2 receptor binding between the D614 and G614 Spike variants, the G614 variant is more resistant to proteolytic cleavage, suggesting a possible mechanism for the increased transduction.

    1. Epidemiology and Global Health
    Gwenan M Knight et al.
    Review Article

    Before the coronavirus 2019 (COVID-19) pandemic began, antimicrobial resistance (AMR) was among the top priorities for global public health. Already a complex challenge, AMR now needs to be addressed in a changing healthcare landscape. Here, we analyse how changes due to COVID-19 in terms of antimicrobial usage, infection prevention, and health systems affect the emergence, transmission, and burden of AMR. Increased hand hygiene, decreased international travel, and decreased elective hospital procedures may reduce AMR pathogen selection and spread in the short term. However, the opposite effects may be seen if antibiotics are more widely used as standard healthcare pathways break down. Over 6 months into the COVID-19 pandemic, the dynamics of AMR remain uncertain. We call for the AMR community to keep a global perspective while designing finely tuned surveillance and research to continue to improve our preparedness and response to these intersecting public health challenges.