Search for asymptomatic carriers of SARS-CoV-2 in healthcare workers during the pandemic: a Spanish experience

Background: Asymptomatic carriers of SARS-CoV-2 can be a vehicle for transmission of the infection. This fact is of particular importance in the case of healthcare workers (HCWs). Design: Cross-sectional study in HCWs in a medium size hospital in the South of Spain. Methods: Between 15 and 25 April 2020, naso- and oropharyngeal PCR determination was performed together with IgG and IgM antibody determination by immunochromatography to the HCWs of the Costa del Sol Hospital in Marbella of the units involved in patient care with COVID-19: Emergencies, Intensive Care and Anesthesia, Internal Medicine and Pneumology. Other units not directly involved in the care of these patients were offered to participate. On the day of sampling, a health questionnaire was answered, reporting symptoms on the same day and in the previous 14 days. Results: Four hundred and ninety-eight HCWs were studied. Two individuals were detected with PCR for SARS-CoV2 positive. Both were asymptomatic on the day of sampling, but one of them had had a COVID-19 compatible picture in the previous two weeks and had positive IgG and IgM; therefore, only one subject was truly asymptomatic carrier (0.2%). Nine workers with positive IgG (1.8%) were detected. Conclusions: The prevalence of asymptomatic carriers among health workers of the services directly involved in the care of patients with COVID-19 was very low in our center. This type of strategy can be one more tool in controlling the pandemic.