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Prevalence of Positive Rapid Antigen Tests After 7-Day Isolation Following SARS-CoV-2 Infection in College Athletes During Omicron Variant Predominance

Educational Objective
To identify the key insights or developments described in this article
1 Credit CME
Key Points

Question  Is the 5-day isolation period after SARS-CoV-2 infection that has been recommended by the US Centers for Disease Control and Prevention sufficient for infected individuals to receive negative test results?

Findings  In this case series, 268 collegiate student athletes who tested positive for SARS-CoV-2 underwent rapid antigen testing starting 7 days after the initial positive test. At 7 days, the results of testing were still positive in 27% of the individuals tested, with a higher percent positive in symptomatic individuals and those infected with the Omicron BA.2 variant.

Meaning  The findings of this study suggest that use of rapid antigen testing to aid in the decision to end isolation may be needed to prevent individuals with infection from leaving isolation prematurely.


Importance  The US Centers for Disease Control and Prevention shortened the recommended isolation period for SARS-CoV-2 infection from 10 days to 5 days in December 2021. It is unknown whether an individual with the infection may still have a positive result to a rapid antigen test and potentially be contagious at the end of this shortened isolation period.

Objective  To estimate the proportion of individuals with SARS-CoV-2 infection whose rapid antigen test is still positive starting 7 days postdiagnosis.

Design, Setting, and Participants  This case series analyzed student athletes at a National Collegiate Athletic Association Division I university campus who tested positive for SARS-CoV-2 between January 3 and May 6, 2022. Individuals underwent rapid antigen testing starting 7 days postdiagnosis to determine whether they could end their isolation period.

Exposures  Rapid antigen testing 7 days after testing positive for SARS-CoV-2.

Main Outcomes and Measures  Rapid antigen test results, symptom status, and SARS-CoV-2 variant identification via campus wastewater analysis.

Results  A total of 264 student athletes (140 [53%] female; mean [SD] age, 20.1 [1.2] years; range, 18-25 years) representing 268 infections (177 [66%] symptomatic, 91 [34%] asymptomatic) were included in the study. Of the 248 infections in individuals who did a day 7 test, 67 (27%; 95% CI, 21%-33%) tests were still positive. Patients with symptomatic infections were significantly more likely to test positive on day 7 vs those who were asymptomatic (35%; 95% CI, 28%-43% vs 11%; 95% CI, 5%-18%; P < .001). Patients with the BA.2 variant were also significantly more likely to test positive on day 7 compared with those with the BA.1 variant (40%; 95% CI, 29%-51% vs 21%; 95% CI, 15%-27%; P = .007).

Conclusions and Relevance  In this case series, rapid antigen tests remained positive in 27% of the individuals after 7 days of isolation, suggesting that the Centers for Disease Control and Prevention–recommended 5-day isolation period may be insufficient in preventing ongoing spread of disease. Further studies are needed to determine whether these findings are present in a more heterogeneous population and in subsequent variants.

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Article Information

Accepted for Publication: August 30, 2022.

Published: October 18, 2022. doi:10.1001/jamanetworkopen.2022.37149

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2022 Tsao J et al. JAMA Network Open.

Corresponding Author: Calvin E. Hwang, MD, Stanford University School of Medicine, 341 Galvez St, Lower Level, Stanford, CA 94305 (highlndr@stanford.edu).

Author Contributions: Dr Hwang had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Tsao, Kussman, Abrams, Hwang.

Acquisition, analysis, or interpretation of data: Tsao, Kussman, Segovia, Boehm, Hwang.

Drafting of the manuscript: Tsao, Boehm, Hwang.

Critical revision of the manuscript for important intellectual content: Kussman, Segovia, Abrams, Hwang.

Statistical analysis: Tsao, Segovia, Hwang.

Obtained funding: Boehm.

Administrative, technical, or material support: Kussman.

Supervision: Kussman.

Conflict of Interest Disclosures: Dr Kussman reported receiving speaking fees from Fresno Madera Medical Society outside the submitted work. Dr Abrams reported owning stock or stock options from AxGen and Cytonics; serving as an unpaid board or committee member for the American Academy of Orthopaedic Surgeons, American Orthopaedic Society for Sports Medicine, and International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; receiving cadaver instruction and equipment for educational purposes from Arthrex and Stryker; receiving consulting fees from Bioventus Inc, Cytonics, Fidia Pharma, and RubiconMD; and serving as an unpaid consultant for TeachAids. No other disclosures were reported.

Funding/Support: The study was funded by the Stanford University Provost’s office.

Role of the Funder/Sponsor: The Stanford University Provost’s office had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: We thank the Stanford University Provost’s office for funding for the wastewater data collection.

Centers for Disease Control and Prevention. Ending isolation and precautions for people with COVID-19: interim guidance. March 31, 2022. Accessed June 20, 2022. https://www.cdc.gov/coronavirus/2019-ncov/hcp/duration-isolation.html
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