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dc.contributor.authorSah, Pratha
dc.contributor.authorFitzpatrick, Meagan C
dc.contributor.authorZimmer, Charlotte F
dc.contributor.authorAbdollahi, Elaheh
dc.contributor.authorJuden-Kelly, Lyndon
dc.contributor.authorMoghadas, Seyed M
dc.contributor.authorSinger, Burton H
dc.contributor.authorGalvani, Alison P
dc.date.accessioned2021-08-13T12:57:34Z
dc.date.available2021-08-13T12:57:34Z
dc.date.issued2021-08-10
dc.identifier.urihttp://hdl.handle.net/10713/16383
dc.description.abstractQuantification of asymptomatic infections is fundamental for effective public health responses to the COVID-19 pandemic. Discrepancies regarding the extent of asymptomaticity have arisen from inconsistent terminology as well as conflation of index and secondary cases which biases toward lower asymptomaticity. We searched PubMed, Embase, Web of Science, and World Health Organization Global Research Database on COVID-19 between January 1, 2020 and April 2, 2021 to identify studies that reported silent infections at the time of testing, whether presymptomatic or asymptomatic. Index cases were removed to minimize representational bias that would result in overestimation of symptomaticity. By analyzing over 350 studies, we estimate that the percentage of infections that never developed clinical symptoms, and thus were truly asymptomatic, was 35.1% (95% CI: 30.7 to 39.9%). At the time of testing, 42.8% (95% prediction interval: 5.2 to 91.1%) of cases exhibited no symptoms, a group comprising both asymptomatic and presymptomatic infections. Asymptomaticity was significantly lower among the elderly, at 19.7% (95% CI: 12.7 to 29.4%) compared with children at 46.7% (95% CI: 32.0 to 62.0%). We also found that cases with comorbidities had significantly lower asymptomaticity compared to cases with no underlying medical conditions. Without proactive policies to detect asymptomatic infections, such as rapid contact tracing, prolonged efforts for pandemic control may be needed even in the presence of vaccination.en_US
dc.description.urihttps://doi.org/10.1073/pnas.2109229118en_US
dc.language.isoenen_US
dc.publisherNational Academy of Sciences of the United States of Americaen_US
dc.relation.ispartofProceedings of the National Academy of Sciences of the United States of Americaen_US
dc.rightsCopyright © 2021 the Author(s). Published by PNAS.en_US
dc.subjectasymptomatic fractionen_US
dc.subjectcomorbidityen_US
dc.subjectnovel coronavirusen_US
dc.subjectpresymptomaticen_US
dc.subjectsilent transmissionen_US
dc.titleAsymptomatic SARS-CoV-2 infection: A systematic review and meta-analysisen_US
dc.typeArticleen_US
dc.identifier.doi10.1073/pnas.2109229118
dc.identifier.pmid34376550
dc.source.volume118
dc.source.issue34
dc.source.countryUnited States
dc.source.countryUnited States


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