Prevalence of coronavirus disease 2019 (COVID-19) among healthcare professionals working in hospital emergencies during the first-wave peak in 2020 in Porto Alegre, Brazil

Abstract

Background: Very little is known about the frequency of COVID-19 in health care workers, particularly in developing countries Materials and Methods: Cohort study to assess the prevalence of COVID-19 in professionals working in the emergency facilities of five large tertiary hospitals located in Porto Alegre, Southern Brazil (population 1.4 million). Workers were evaluated on July 20-24 (2020), and again after three weeks. At each encounter, clinical data were obtained, and a blood sample was taken by finger pricking for antibody detection (Standard Q COVID-19 IgM/IgG Duo-Biosensor, South Korea) Results: Participants (n=1,163) were mostly female (66.6%), and median age was 38 years-old. Close contact with COVID-19 was reported by 82.3%. In the first phase of study, a total of 5.5% (n=64) were found to have antibodies against COVID-19 (26 IgM; 19 IgG; 19 both), including 34.6% (n=27) of workers previously diagnosed with COVID-19 (n=78). After three weeks, seropositivity was 5.6% (17 IgM; 17 IgG; 17 both). IgM and IgG became negative in the second study evaluation for 55.3% and 50.0% of participants who were previously positive for these antibodies, respectively Conclusion: This study reveals that a large proportion of health care professionals had been exposed to SARS-CoV-2, developed COVID-19 and presented with antibodies against the disease. For most patients, antibodies disappear over time which may have important implications for the detection of positive cases in epidemiological studies.