Incidence of COVID-19 recurrence among large cohort of healthcare employees

To quantify COVID-19 recurrence among clinical and nonclinical healthcare employees with SARS-CoV-2 IgG antibodies or prior COVID-19 infection. This prospective, cohort study collected and resulted SARS-CoV-2 IgG serum samples as positive or negative from June 8 to July 10, 2020 from a convenience sample of 16,233 adult participants employed by a large Midwestern healthcare system. Documented positive polymerase chain reaction test results representing COVID-19 infections were recorded up to four months prior to and post-IgG testing. Nine hundred and thirteen (6.12%) participants, including 45 (4.93%) IgG positive participants, experienced COVID-19 infections after study initiation, representing a 51% increased risk of COVID-19 infection among IgG positive participants (IRR = 1.51). Regressions adjusted for documented disparities showed no difference in COVID-19 infection by IgG status (OR=1.19; P = .3117) but significantly greater odds in COVID-19 recurrence among participants with a prior documented COVID-19 infection (OR=1.93; P < .0001). SARS-CoV-2 IgG antibodies and prior COVID-19 infection do not appear to offer meaningful protection against COVID-19 recurrence in healthcare workers. Recurrence would impact decisions regarding ongoing healthcare resource utilization. This study can inform considerations for vaccine administration to vulnerable groups.