Quantifying the relationship between SARS-CoV-2 viral load and infectiousness

DOI record: { "DOI": "10.7554/elife.69302", "ISSN": [ "2050-084X" ], "URL": "http://dx.doi.org/10.7554/eLife.69302", "abstract": "<jats:p>The relationship between SARS-CoV-2 viral load and infectiousness is poorly known. Using data from a cohort of cases and high-risk contacts, we reconstructed viral load at the time of contact and inferred the probability of infection. The effect of viral load was larger in household contacts than in non-household contacts, with a transmission probability as large as 48% when the viral load was greater than 10<jats:sup>10</jats:sup> copies per mL. The transmission probability peaked at symptom onset, with a mean probability of transmission of 29%, with large individual variations. The model also projects the effects of variants on disease transmission. Based on the current knowledge that viral load is increased by two- to eightfold with variants of concern and assuming no changes in the pattern of contacts across variants, the model predicts that larger viral load levels could lead to a relative increase in the probability of transmission of 24% to 58% in household contacts, and of 15% to 39% in non-household contacts.</jats:p>", "accepted": { "date-parts": [ [ 2021, 9, 1 ] ] }, "alternative-id": [ "10.7554/eLife.69302" ], "article-number": "e69302", "assertion": [ { "group": { "name": "peer_review_taxonomy" }, "label": "Peer review transparency", "name": "peer_review_transparency", "value": "single anonymised" }, { "group": { "name": "peer_review_taxonomy" }, "label": "Peer review interaction", "name": "peer_review_interaction", "value": "other reviewer(s), editor" }, { "group": { "name": "peer_review_taxonomy" }, "label": "Peer review published", "name": "peer_review_published", "value": "review summaries, review reports, 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an outbreak of SARS COV-2 variant 501Y.V2 in an elderly nursing home but reduced transmission and disease severity", "author": "Bailly", "doi-asserted-by": "publisher", "journal-title": "Clinical Infectious Diseases", "key": "bib2", "year": "2021" }, { "DOI": "10.1073/pnas.1704011114", "article-title": "Zika plasma viral dynamics in nonhuman primates provides insights into early infection and antiviral strategies", "author": "Best", "doi-asserted-by": "publisher", "first-page": "8847", "journal-title": "PNAS", "key": "bib3", "volume": "114", "year": "2017" }, { "DOI": "10.1016/S1473-3099(20)30287-5", "article-title": "Epidemiology and transmission of COVID-19 in 391 cases and 1286 of their close contacts in Shenzhen, China: a retrospective cohort study", "author": "Bi", "doi-asserted-by": "publisher", "first-page": "911", "journal-title": "The Lancet. Infectious Diseases", "key": "bib4", "volume": "20", "year": "2020" }, { "DOI": "10.1056/NEJMoa2016638", "article-title": "A randomized trial of hydroxychloroquine as postexposure prophylaxis for Covid-19", "author": "Boulware", "doi-asserted-by": "publisher", "first-page": "517", "journal-title": "New England Journal of Medicine", "key": "bib5", "volume": "383", "year": "2020" }, { "article-title": "The early phase of the COVID-19 outbreak in Lombardy, Italy", "author": "Cereda", "key": "bib6", "unstructured": "Cereda D, Tirani M, Rovida F, Demicheli V, Ajelli M, Poletti P, Trentini F, Guzzetta G, Marziano V, Barone A, Magoni M, Deandrea S, Diurno G, Lombardo M, Faccini M, Pan A, Bruno R, Pariani E, Grasselli G, Piatti A, Gramegna M, Baldanti F, Melegaro A, Merler S. 2020. The early phase of the COVID-19 outbreak in Lombardy, Italy. arXiv. https://arxiv.org/abs/2003.09320.", "volume-title": "arXiv", "year": "2020" }, { "DOI": "10.7554/eLife.65774", "article-title": "Heterogeneity in transmissibility and shedding SARS-CoV-2 via droplets and aerosols", "author": "Chen", "doi-asserted-by": "publisher", "journal-title": "eLife", "key": "bib7", "volume": "10", "year": "2021" }, { "DOI": "10.18637/jss.v080.i03", "article-title": "Parameter estimation in nonlinear mixed effect models using saemix, an R implementation of the SAEM algorithm", "author": "Comets", "doi-asserted-by": "publisher", "first-page": "1", "journal-title": "Journal of Statistical Software", "key": "bib8", "volume": "80", "year": "2017" }, { "DOI": "10.1016/j.jinf.2021.07.031", "article-title": "SARS-CoV-2 viral dynamics in infections with alpha and beta variants of concern in the french community", "author": "Cosentino", "doi-asserted-by": "publisher", "journal-title": "The Journal of Infection", "key": "bib9", "volume": "S0163-4453", "year": "2021" }, { "DOI": "10.1214/aos/1018031103", "article-title": "Convergence of a stochastic approximation version of the EM algorithm", "author": "Delyon", "doi-asserted-by": "publisher", "first-page": "94", "journal-title": "The Annals of Statistics", "key": "bib10", "volume": "27", "year": "1999" }, { "DOI": "10.1073/pnas.2021830118", "article-title": "Exhaled aerosol increases with COVID-19 infection, age, and obesity", "author": "Edwards", "doi-asserted-by": "publisher", "journal-title": "PNAS", "key": "bib11", "volume": "118", "year": "2021" }, { "DOI": "10.1101/2021.05.26.21257835", "article-title": "Inferring SARS-CoV-2 variant within-host kinetics", "author": "Elie", "doi-asserted-by": "publisher", "key": "bib12", "volume-title": "medRxiv", "year": "2021" }, { "DOI": "10.1126/science.abb6936", "article-title": "Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing", "author": "Ferretti", "doi-asserted-by": "publisher", "journal-title": "Science", "key": "bib13", "volume": "368", "year": "2020" }, { "DOI": "10.1101/2021.01.12.20249080", "article-title": "Early analysis of a potential link between viral load and the N501Y mutation in the SARS-COV-2 spike protein", "author": "Golubchik", "doi-asserted-by": "publisher", "key": "bib14", "volume-title": "medRxiv", "year": "2021" }, { "DOI": "10.1002/psp4.12543", "article-title": "Timing of antiviral treatment initiation is critical to reduce SARS-CoV-2 viral load", "author": "Gonçalves", "doi-asserted-by": "publisher", "first-page": "509", "journal-title": "CPT: Pharmacometrics & Systems Pharmacology", "key": "bib15", "volume": "9", "year": "2020" }, { "DOI": "10.1371/journal.pcbi.1008785", "article-title": "SARS-CoV-2 viral dynamics in non-human primates", "author": "Gonçalves", "doi-asserted-by": "publisher", "journal-title": "PLOS Computational Biology", "key": "bib16", "volume": "17", "year": "2021" }, { "DOI": "10.1038/s41591-020-0869-5", "article-title": "Temporal dynamics in viral shedding and transmissibility of COVID-19", "author": "He", "doi-asserted-by": "publisher", "first-page": "672", "journal-title": "Nature Medicine", "key": "bib17", "volume": "26", "year": "2020" }, { "DOI": "10.1126/science.abi5273", "article-title": "Estimating infectiousness throughout SARS-CoV-2 infection course", "author": "Jones", "doi-asserted-by": "publisher", "journal-title": "Science", "key": "bib18", "volume": "373", "year": "2021" }, { "DOI": "10.1101/2020.09.25.20201772", "article-title": "Kinetics of SARS-CoV-2 infection in the human upper and lower respiratory tracts and their relationship with infectiousness", "author": "Ke", "doi-asserted-by": "publisher", "key": "bib19", "volume-title": "medRxiv", "year": "2020" }, { "DOI": "10.1101/2021.07.12.21260208", "article-title": "Daily sampling of early SARS-CoV-2 infection reveals substantial heterogeneity in infectiousness", "author": "Ke", "doi-asserted-by": "publisher", "key": "bib20", "volume-title": "medRxiv", "year": "2021" }, { "DOI": "10.1093/infdis/jiab082", "article-title": "S-variant SARS-CoV-2 lineage B1.1.7 is associated with significantly higher viral loads in samples tested by ThermoFisher TaqPath RT-qPCR", "author": "Kidd", "doi-asserted-by": "publisher", "first-page": "1666", "journal-title": "The Journal of Infectious Diseases", "key": "bib21", "volume": "223", "year": "2021" }, { "DOI": "10.7326/M20-0504", "article-title": "The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application", "author": "Lauer", "doi-asserted-by": "publisher", "first-page": "577", "journal-title": "Annals of Internal Medicine", "key": "bib22", "volume": "172", "year": "2020" }, { "DOI": "10.1038/s41591-021-01316-7", "article-title": "Initial report of decreased SARS-CoV-2 viral load after inoculation with the BNT162b2 vaccine", "author": "Levine-Tiefenbrun", "doi-asserted-by": "publisher", "first-page": "790", "journal-title": "Nature Medicine", "key": "bib23", "volume": "27", "year": "2021" }, { "DOI": "10.1101/2021.03.08.434499", "article-title": "The N501Y spike substitution enhances SARS-CoV-2 transmission", "author": "Liu", "doi-asserted-by": "publisher", "key": "bib24", "volume-title": "bioRxiv", "year": "2021" }, { "DOI": "10.1038/s41467-018-06215-z", "article-title": "Ebola viral dynamics in nonhuman primates provides insights into virus immuno-pathogenesis and antiviral strategies", "author": "Madelain", "doi-asserted-by": "publisher", "journal-title": "Nature Communications", "key": "bib25", "volume": "9", "year": "2018" }, { "DOI": "10.1038/s41586-020-2558-4", "article-title": "Hydroxychloroquine use against SARS-CoV-2 infection in non-human primates", "author": "Maisonnasse", "doi-asserted-by": "publisher", "first-page": "584", "journal-title": "Nature", "key": "bib26", "volume": "585", "year": "2020" }, { "DOI": "10.1016/S1473-3099(20)30985-3", "article-title": "Transmission of COVID-19 in 282 clusters in Catalonia, Spain: a cohort study", "author": "Marks", "doi-asserted-by": "publisher", "first-page": "629", "journal-title": "The Lancet Infectious Diseases", "key": "bib27", "volume": "21", "year": "2021" }, { "article-title": "Single dose of a mRNA SARS-CoV-2 vaccine is associated with lower nasopharyngeal viral load among nursing home residents with asymptomatic COVID-19", "author": "McEllistrem", "journal-title": "Clinical Infectious Diseases", "key": "bib28", "volume": "73", "year": "2021" }, { "DOI": "10.1056/NEJMoa2021801", "article-title": "A Cluster-Randomized trial of hydroxychloroquine for prevention of Covid-19", "author": "Mitjà", "doi-asserted-by": "publisher", "first-page": "417", "journal-title": "New England Journal of Medicine", "key": "bib29", "volume": "384", "year": "2021" }, { "DOI": "10.1101/2021.05.28.21258011", "article-title": "SARS-CoV-2 infectious virus, viral RNA in nasopharyngeal swabs, and serostatus of symptomatic COVID-19 outpatients in the United States", "author": "Mollan", "doi-asserted-by": "publisher", "key": "bib30", "volume-title": "medRxiv", "year": "2021" }, { "author": "Monolix version 2020R1", "key": "bib31", "unstructured": "Monolix version 2020R1. 2019. LIXOFT. Antony, France: Lixoft SAS, 2019. http://lixoft.com/products/monolix/.", "volume-title": "Antony, France: Lixoft SAS, 2019", "year": "2019" }, { "DOI": "10.1038/s41591-021-01378-7", "article-title": "COVID-19 in Amazonas, Brazil, was driven by the persistence of endemic lineages and p.1 emergence", "author": "Naveca", "doi-asserted-by": "publisher", "first-page": "1230", "journal-title": "Nature Medicine", "key": "bib32", "volume": "27", "year": "2021" }, { "DOI": "10.1073/pnas.2017962118", "article-title": "Modeling SARS-CoV-2 viral kinetics and association with mortality in hospitalized patients from the French COVID cohort", "author": "Néant", "doi-asserted-by": "publisher", "journal-title": "PNAS", "key": "bib33", "volume": "118", "year": "2021" }, { "DOI": "10.1101/2021.03.19.21253971", "article-title": "SARS-CoV-2 variants of concern are associated with lower RT-PCR amplification cycles between January and march 2021 in France", "author": "Roquebert", "doi-asserted-by": "publisher", "key": "bib34", "volume-title": "medRxiv", "year": "2021" }, { "DOI": "10.1016/j.envint.2020.106039", "article-title": "Aerosol transmission of SARS-CoV-2? Evidence, prevention and control", "author": "Tang", "doi-asserted-by": "publisher", "journal-title": "Environment International", "key": "bib35", "volume": "144", "year": "2020" }, { "DOI": "10.1016/j.jinf.2021.04.023", "article-title": "The 501Y.V2 SARS-CoV-2 variant has an intermediate viral load between the 501Y.V1 and the historical variants in nasopharyngeal samples from newly diagnosed COVID-19 patients", "author": "Teyssou", "doi-asserted-by": "publisher", "first-page": "119", "journal-title": "Journal of Infection", "key": "bib36", "volume": "83", "year": "2021" }, { "DOI": "10.1056/NEJMoa2107058", "article-title": "Prevention and attenuation of Covid-19 with the BNT162b2 and mRNA-1273 vaccines", "author": "Thompson", "doi-asserted-by": "publisher", "first-page": "320", "journal-title": "New England Journal of Medicine", "key": "bib37", "volume": "385", "year": "2021" }, { "DOI": "10.1038/s41467-020-20568-4", "article-title": "Duration and key determinants of infectious virus shedding in hospitalized patients with coronavirus disease-2019 (COVID-19)", "author": "van Kampen", "doi-asserted-by": "publisher", "journal-title": "Nature Communications", "key": "bib38", "volume": "12", "year": "2021" }, { "DOI": "10.1038/s41591-020-0822-7", "article-title": "Estimating clinical severity of COVID-19 from the transmission dynamics in Wuhan, China", "author": "Wu", "doi-asserted-by": "publisher", "first-page": "506", "journal-title": "Nature Medicine", "key": "bib39", "volume": "26", "year": "2020" } ], "reference-count": 39, "references-count": 39, "relation": { "has-preprint": [ { "asserted-by": "subject", "id": "10.1101/2021.05.07.21256341", "id-type": "doi" }, { "asserted-by": "object", "id": "10.1101/2021.05.07.21256341", "id-type": "doi" } ], "has-review": [ { "asserted-by": "object", "id": "10.7554/eLife.69302.sa1", "id-type": "doi" }, { "asserted-by": "object", "id": "10.7554/eLife.69302.sa2", "id-type": "doi" } ] }, "resource": { "primary": { "URL": "https://elifesciences.org/articles/69302" } }, "score": 1, "short-title": [], "source": "Crossref", "subject": [], "subtitle": [], "title": "Quantifying the relationship between SARS-CoV-2 viral load and infectiousness", "type": "journal-article", "update-policy": "https://doi.org/10.7554/elife.69302", "volume": "10" }