Positivity of antigen test in healthcare workers in the first week after diagnosis of SARS-CoV-2 infection

BACKGROUND // The Surveillance and Control Strategy against COVID- 19 of the spanish Ministry of Health focuses, since December 2021, on actions aimed at vulnerable people and areas, including healthcare professionals. According to these protocols, a diagnostic test for acute infection (PDIA), with a negative result, is required prior to returning to work (at least five days after the start of clinical practice). The aim of the study was to analyze the proportion of positive antigen (Ag) test results in the first week of diagnosis among healthcare professionals in a university hospital belonging to the province of A Coruna (Spain). METHODS // We calculated the proportion of healthcare professionals who had symptoms on the 5th day after diagnosis of COVID-19 between January and March 2022, and the proportion of Ag tests performed after returning to work with positive results. These results were compared according to the month and 95% confidence intervals were calculated. RESULTS // 1,085 cases of COVID-19 were diagnosed among healthcare professionals. 18.62% (95%CI 16.34-21.63; n=202/1,085) were still symptomatic on the 5th day. 55.27% (95% CI 51.92-58.58; n=488/833) of the Ag tests performed after return to work were positive. The mean number of days to perform the Ag test after diagnosis was 6.76 days (SD 0.76). CONCLUSIONS // Our results show a high proportion of positive results one week after diagnosis of COVID-19 in asymptomatic patients. Taking into account that in the general population, discharge is based on clinical and temporal criteria, and assuming that not every positive test indicates infectivity, adopting a strategy similar to the rest of the population in healthcare workers would be considered plausible.