Results from a Test-to-Release from Isolation Strategy Among Fully Vaccinated National Football League Players and Staff Members with COVID-19 — United States, December 14–19, 2021
Christina Mack, Erin B. Wasserman, Marie E. Killerby, Rieza H. Soelaeman, Aron J. Hall, Adam MacNeil, Deverick J. Anderson, Patti Walton, Saamir Pasha, Emily Myers, Catherine O’Neal, Christopher J. Hostler, Navdeep Singh, Thom Mayer, Allen K. Sills
Abstract
During December 2021, the United States experienced a surge in COVID-19 cases, coinciding with predominance of the SARS-CoV-2 B.1.1.529 (Omicron) variant (1). During this surge, the National Football League (NFL) and NFL Players Association (NFLPA) adjusted their protocols for test-to-release from COVID-19 isolation on December 16, 2021, based on analytic assessments of their 2021 test-to-release data. Fully vaccinated* persons with COVID-19 were permitted to return to work once they were asymptomatic or fever-free and experiencing improving symptoms for 24 hours, and after two negative or high cycle-threshold (Ct) results (Ct35) from either of two reverse transcription-polymerase chain reaction (RT-PCR) tests (2). This report describes data from NFL's SARS-CoV-2 testing program (3) and time to first negative or Ct35 result based on serial COVID-19 patient testing during isolation. Among this occupational cohort of 173 fully vaccinated adults with confirmed COVID-19 during December 14-19, 2021, a period of Omicron variant predominance, 46% received negative test results or had a subsequent RT-PCR test result with a Ct35 by day 6 postdiagnosis (i.e., concluding 5 days of isolation) and 84% before day 10. The proportion of persons with positive test results decreased with time, with approximately one half receiving positive RT-PCR test results after postdiagnosis day 5. Although this test result does not necessarily mean these persons are infectious (RT-PCR tests might continue to return positive results long after an initial positive result) (4), these findings indicate that persons with * Fully vaccinated was defined as 14 days after primary vaccination series completion, with or without a booster. Partially vaccinated was defined by NFL as receipt of 1 dose of a 2-dose series or <14 days after primary vaccine series completion. Under NFL-NFLPA protocols, persons with 1 dose of a 2-dose mRNA vaccination series and a documented history of COVID-19 were subject to the same requirements as were fully vaccinated persons in the NFL-NFLPA protocols; however, these persons were excluded from analyses summarizing the test-to-release from isolation strategy. SARS-CoV-2 tests included either laboratory-based real-time RT-PCR (BioReference Laboratories RT-PCR assay [Roche Cobas assay, Roche]) or point of care (POC) RT-PCR (Mesa Biotech Accula SARS-CoV-2 test, Mesa Biotech Inc.). The Roche Cobas RT-PCR test used received Food and Drug Administration (FDA) Emergency Use Authorization as a qualitative diagnostic assay with a Ct cutoff of >40. Use of this assay with alternative Ct cutoffs is not authorized by FDA. The Mesa Biotech Accula test produces a qualitative result (positive/negative) without Ct values.