NBA study shows persistent positive cases do not transmit COVID-19 after recovery
A cohort study of the closed-campus National Basketball Association occupational health program found that people who recovered clinically from COVID-19 but continued to test positive did not transmit SARS-CoV-2 to others in close proximity.
“The findings support the CDC’s time-based recommendation, noting that emerging variants will drive further research here,” Christina D. Mack, PhD, MSPH, vice president of epidemiology and clinical evidence at IQVIA, a health information technology and clinical research firm, told Healio Primary Care.
Mack and colleagues conducted a retrospective cohort study using data collected between June 11, 2020, and Oct. 19, 2020, from the NBA closed-campus occupational health program in Orlando, Florida. The program required 3,648 players, staff and vendors to undergo daily RT-PCR testing and ad hoc serological testing for SARS-CoV-2 antibodies. The study’s main outcome measure was SARS-CoV-2 transmission after interaction with an individual who clinically recovered from COVID-19 but had at least one postinfection positive RT-PCR result. The researchers monitored cases for a mean 51 days, up to 100 days.
Among the study population, 36 participants were persistent positive cases (67% aged younger than 30 years; 94% men). The researchers reported that antibodies were found in 33 participants who remained asymptomatic after the postinfection positive RT-PCR result.
The persistent positive RT-PCR test results “typically” had cycle threshold values above the Roche cobas SARS-CoV-2 limit of detection, according to the researchers. There were no transmission events or secondary infections of SARS-CoV-2 detected during the study, they wrote.
“Our study suggests that individuals who continue to test positive by RT-PCR for SARS-CoV-2 after meeting CDC criteria for discontinuation of isolation were not infectious to others during regular unmasked exposures,” Mack and colleagues wrote.
In a related editorial, James W. Salazar, MD, MAS, a resident physician at the University of California, San Francisco, and editorial fellow at JAMA Internal Medicine, and Mitchell H. Katz, MD, president and CEO of NYC Health + Hospitals and deputy editor of JAMA Internal Medicine, said the study offers “convincing evidence that a symptom-based strategy for discontinuation of precautions is the right approach,” but the implications for the general public are limited.
“In many ways, the NBA bubble season, with a fixed population of players and supportive personnel who participated in daily testing and many who were exposed regularly to high-risk, indoor, unmasked, close-contact activities, was an ideal experiment to test the transmissibility of persistently positive individuals,” they wrote. “However, this was a group of predominantly young, healthy individuals, and none of the persistently positive individuals in this study required hospitalization. As such, these results should not be generalized to those who are immunocompromised or those with severe COVID-19 infections.”
References:
- Mack CD, et al. JAMA Intern Med. 2021;doi:10.1001/jamainternmed.2021.2114.
- Salazar JW & Katz MH. JAMA Intern Med. 2021;doi:10.1001/jamainternmed.2021.2121.
Perspective
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The study supports the notion that persistent positivity post-recovery from COVID-19 is not associated with contagiousness and that repeat PCR testing is not necessary. Infectivity is a function of several variables and positive PCR results with high-cycle threshold values and non-replicative virus is not sufficient to lead to transmission. Using a time-based approach to discontinue isolation procedures should be standard.
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