JAMA Intern Med. 2021 Apr 22. doi: 10.1001/jamainternmed.2021.2114. Online ahead of print.
IMPORTANCE: Clinical data are lacking regarding the risk of viral transmission from individuals who have positive reverse-transcription-polymerase chain reaction (RT-PCR) SARS-CoV-2 test results after recovery from COVID-19.
OBJECTIVE: To describe case characteristics, including viral dynamics and transmission of infection, for individuals who have clinically recovered from SARS-CoV-2 infection but continued to have positive test results following discontinuation of isolation precautions.
DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study used data collected from June 11, 2020, to October 19, 2020, as part of the National Basketball Association (NBA) closed campus occupational health program in Orlando, Florida, which required daily RT-PCR testing and ad hoc serological testing for SARS-CoV-2 IgG antibodies. Nearly 4000 NBA players, staff, and vendors participated in the NBA's regular and postseason occupational health program in Orlando. Persistent positive cases were those who recovered from a documented SARS-CoV-2 infection, satisfied US Centers for Disease Control and Prevention criteria for discontinuation of isolation precautions, and had at least 1 postinfection positive RT-PCR test(s) result.
EXPOSURES: Person-days of participation in indoor, unmasked activities that involved direct exposure between persistent positive cases and noninfected individuals.
MAIN OUTCOMES AND MEASURES: Transmission of SARS-CoV-2 following interaction with persistent positive individuals, as measured by the number of new COVID-19 cases in the Orlando campus program.
RESULTS: Among 3648 individuals who participated, 36 (1%) were persistent positive cases, most of whom were younger than 30 years (24 [67%]) and male (34 [94%]). Antibodies were detected in 33 individuals (91.7%); all remained asymptomatic following the index persistent positive RT-PCR result. Cycle threshold values for persistent positive RT-PCR test results were typically above the Roche cobas SARS-CoV-2 limit of detection. Cases were monitored for up to 100 days (mean [SD], 51 [23.9] days), during which there were at least 1480 person-days of direct exposure activities, with no transmission events or secondary infections of SARS-CoV-2 detected (0 new cases).
CONCLUSIONS AND RELEVANCE: In this retrospective cohort study of the 2020 NBA closed campus occupational health program, recovered individuals who continued to test positive for SARS-CoV-2 following discontinuation of isolation were not infectious to others. These findings support time-based US Centers of Disease Control and Prevention recommendations for ending isolation.