Prevalence and Factors Associated With Antigen Test Positivity Following SARS-CoV-2 Infection Among Health Care Workers in Los Angeles.

Surges of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among health care workers (HCWs) have led to critical staffing shortages. From January 4 to February 4, 2022, we implemented a return-to-work antigen testing program for HCWs, and 870 HCWs participated. Antigen test positivity was 60.5% for those ≤5 days from symptom onset or positive polymerase chain reaction (PCR), and 47.4% were positive at day 7. Antigen positivity was associated with receiving a booster vaccination and being ≤6 days from symptom onset or PCR test, but not age or a symptomatic infection. Rapid antigen testing can be a useful tool to guide return-to-work and isolation precautions for HCWs following infection.