Comparative analyses of eighteen rapid antigen tests and RT-PCR for COVID-19 quarantine and surveillance-based isolation.

Background: Rapid antigen (RA) tests are being increasingly employed to detect SARS-CoV-2 infections in quarantine and surveillance. Prior research has focused on RT-PCR testing, a single RA test, or generic diagnostic characteristics of RA tests in assessing testing strategies. Methods: We have conducted a comparative analysis of the post-quarantine transmission, the effective reproduction number during serial testing, and the false-positive rates for 18 RA tests with emergency use authorization from The United States Food and Drug Administration and an RT-PCR test. To quantify the extent of transmission, we developed an analytical mathematical framework informed by COVID-19 infectiousness, test specificity, and temporal diagnostic sensitivity data. Results: We demonstrate that the relative effectiveness of RA tests and RT-PCR testing in reducing post-quarantine transmission depends on the quarantine duration and the turnaround time of testing results. For quarantines of two days or shorter, conducting a RA test on exit from quarantine reduces onward transmission more than a single RT-PCR test (with a 24-h delay) conducted upon exit. Applied to a complementary approach of performing serial testing at a specified frequency paired with isolation of positives, we have shown that RA tests outperform RT-PCR with a 24-h delay. The results from our modeling framework are consistent with quarantine and serial testing data collected from a remote industry setting. Conclusions: These RA test-specific results are an important component of the tool set for policy decision-making, and demonstrate that judicious selection of an appropriate RA test can supply a viable alternative to RT-PCR in efforts to control the spread of disease.

Worksite Temperature Screening for COVID-19.

OBJECTIVE: To determine whether temperature screening is useful in detecting and reducing workplace transmission of SARS-CoV-2. METHODS: A survey was conducted to determine whether temperature screening successfully identified workers with coronavirus disease 2019 (COVID-19) among a convenience sample of medical directors of multinational corporations in a wide range of industries. RESULTS: More than 15 million screenings were performed by 14 companies. Fewer than 700 episodes of fever were identified. Of these, only about 53 cases of COVID-19 were detected. By contrast about 2000 workers with diagnosed COVID-19 were in the workplace and not detected by screening. CONCLUSIONS: One case of COVID-19 was identified by screening for approximately every 40 cases that were missed. Worksite temperature screening was ineffective for detecting workers with COVID-19 and is not recommended.