Optimizing SARS-CoV-2 Surveillance in the United States: Insights From the National Football League Occupational Health Program.

BACKGROUND

Evidence to understand effective strategies for surveillance and early detection of SARS-CoV-2 is limited.

OBJECTIVE

To describe the results of a rigorous, large-scale COVID-19 testing and monitoring program.

DESIGN

The U.S. National Football League (NFL) and the NFL Players Association (NFLPA) instituted a large-scale COVID-19 monitoring program involving daily testing using 2 reverse transcription polymerase chain reaction (RT-PCR) platforms (Roche cobas and Thermo Fisher QuantStudio), a transcription-mediated amplification platform (Hologic Panther), and an antigen point-of-care (aPOC) test (Quidel Sofia).

SETTING

32 NFL clubs in 24 states during the 2020 NFL season.

PARTICIPANTS

NFL players and staff.

MEASUREMENTS

SARS-CoV-2 test results were described in the context of medically adjudicated status. Cycle threshold (Ct) values are reported when available.

RESULTS

A total of 632 370 tests administered across 11 668 persons identified 270 (2.4%) COVID-19 cases from 1 August to 14 November 2020. Positive predictive values ranged from 73.0% to 82.0% across the RT-PCR platforms. High Ct values (33 to 37) often indicated early infection. For the first positive result, the median Ct value was 32.77 (interquartile range, 30.02 to 34.72) and 22% of Ct values were above 35. Among adjudicated COVID-19 cases tested with aPOC, 42.3% had a negative result. Positive concordance between aPOC test result and adjudicated case status increased as viral load increased.

LIMITATIONS

Platforms varied by laboratory, and test variability may reflect procedural differences.

CONCLUSION

Routine RT-PCR testing allowed early detection of infection. Cycle threshold values provided a useful guidepost for understanding results, with high values often indicating early infection. Antigen POC testing was unable to reliably rule out COVID-19 early in infection.

PRIMARY FUNDING SOURCE

The NFL and the NFLPA.