Duration of viral infectiousness and correlation with symptoms and diagnostic testing in non-hospitalized adults during acute SARS-CoV-2 infection: A longitudinal cohort study

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Abstract

Background

Guidelines for SARS-CoV-2 have relied on limited data on duration of viral infectiousness and correlation with COVID-19 symptoms and diagnostic testing.

Methods

We enrolled ambulatory adults with acute SARS-CoV-2 infection and performed serial measurements of COVID-19 symptoms, nasal swab viral RNA, nucleocapsid (N) and spike (S) antigens, and replication-competent SARS-CoV-2 by culture. We determined average time from symptom onset to a first negative test result and estimated risk of infectiousness, as defined by a positive viral culture.

Results

Among 95 adults, median [interquartile range] time from symptom onset to first negative test result was 9 [5] days, 13 [6] days, 11 [4] days, and >19 days for S antigen, N antigen, viral culture growth, and viral RNA by RT-PCR, respectively. Beyond two weeks, viral cultures and N antigen titers were rarely positive, while viral RNA remained detectable among half (26/51) of participants tested 21-30 days after symptom onset. Between 6-10 days from symptom onset, N antigen was strongly associated with viral culture positivity (relative risk=7.61, 95% CI: 3.01-19.2), whereas neither viral RNA nor symptoms were associated with culture positivity. During the 14 days following symptom onset, presence of N antigen (adjusted relative risk=7.66, 95% CI: 3.96-14.82), remained strongly associated with viral culture positivity, regardless of COVID-19 symptoms.

Conclusions

Most adults have replication-competent SARS-CoV-2 for 10-14 after symptom onset, and N antigen testing is a strong predictor of viral infectiousness. Within two weeks from symptom onset, N antigen testing, rather than absence of symptoms or viral RNA, should be used to safely discontinue isolation.

Funding

Bill and Melinda Gates Foundation

Article activity feed

  1. Strength of evidence

    Reviewers: G.C.K. Mak (Public Health Laboratory Services Branch) | ๐Ÿ“—๐Ÿ“—๐Ÿ“—๐Ÿ“—โ—ป๏ธ
    D.R. Hardie (University of Cape Town Faculty of Health Sciences) | ๐Ÿ“˜๐Ÿ“˜๐Ÿ“˜๐Ÿ“˜๐Ÿ“˜

  2. Gannon C.K. Mak

    Review 1: "Duration of Viral Infectiousness and Correlation with Symptoms and Diagnostic Testing in Non-hospitalized Adults During Acute SARS-CoV-2 Infection: A Longitudinal Cohort Study"

    This preprint assesses the duration of viral infectiousness and correlation with symptoms during an acute SARS-CoV-2 Infection. The reviewers find this study to be reliable to strong, stating that the study was well designed and confirms previous research findings.

  3. Diana Ruth Hardie

    Review 2: "Duration of Viral Infectiousness and Correlation with Symptoms and Diagnostic Testing in Non-hospitalized Adults During Acute SARS-CoV-2 Infection: A Longitudinal Cohort Study"

    This preprint assesses the duration of viral infectiousness and correlation with symptoms during an acute SARS-CoV-2 Infection. The reviewers find this study to be reliable to strong, stating that the study was well designed and confirms previous research findings.