Seroprevalence and seroconversion rates to SARS-CoV-2 in interns, residents, and medical doctors in a University Hospital in Bogota, Colombia

Objectives To determine the prevalence of antibodies to SARS-CoV-2 and the incidence of seroconversion in the first month of follow-up among interns, residents, and medical doctors attending patients at a University Hospital, to explore for associations of seroprevalence and seroconversion with risk factors and symptoms compatible with COVID-19, and to explore the concordance of CLA, LFA, and ELFA. Design or methods We conducted a cross-sectional and a prospective study among medical doctors and medical trainees at Hospital Universitario San Ignacio in Bogota (Colombia) during June, July, and August to assess seroprevalence and seroconversion rates in this population was performed using CLA IgG for SARS-CoV-2. LFA IgG and IgM and ELFA IgM were also determined to explore concordance with CLA IgG. Results At baseline, 8 (2.28% 95%CI 1.16-4.43%) individuals were IgG positive for SARS-CoV-2 by CLA. At the end of the study, 21 (5.98% 95%CI 3.94-8.97%) individuals seroconverted by CLA IgG. In all, 29 individuals had IgG by CLA and of these 11 (3.13% 95%CI 1.76-5.52%) were asymptomatic. No associations with risk factors for infection were identified. CLA had moderate concordance with LFA IgG and ELFA, but minimal with LFA IgM. Conclusions Our report is one of the first in Latina America on seroprevalence and seroconversion rates in medical healthcare workers. It emphasizes the importance of avoiding focusing only on symptomatic individuals to screen this population for SARS-CoV-2 infection, since of all individuals that have evidence of previous infection many (37.93%) may be pre-symptomatic or asymptomatic and may contribute to infection/disease spread.