Seroprevalence of SARS-CoV-2 antibodies, associated epidemiological factors and antibody kinetics among healthcare workers in Connecticut.

Summary Background Healthcare workers (HCWs) are at the front line of the ongoing coronavirus pandemic. Comprehensively evaluating SARS-CoV-2 seroprevalence among HCWs in a large healthcare system could help identify the impact that epidemiological factors and presence of symptoms have on immune response to the infection over time. Aim To determine the seroprevalence of SARS-CoV-2 specific antibodies among healthcare workers (HCWs), to identify associated epidemiological factors and to study antibody kinetics. Methods We completed a longitudinal evaluation of the seroprevalence and epidemiology of SARS-CoV-2 specific antibodies in approximately 30,000 HCWs in the largest healthcare system in the State of Connecticut. Findings The baseline prevalence of SARS-CoV-2 antibody among 6,863 HCWs was 6.3% (95% CI: 5.7%-6.9%) and was highest among patient care support (16.7%), medical assistants (9.1%), and nurses (8.2%) and lower for physicians (3.8%) and advanced practice providers (4.5%). Seroprevalence was significantly higher among African Americans (OR 3.26 compared to Caucasians, 95% CI 1.77-5.99), in participants with at least one COVID symptom (OR 3.00, 95% CI 1.92-4.68), and in those reporting prior quarantine (OR 3.83, 95% CI 2.57-5.70). No symptoms were reported in 24% of the seropositive participants. Among the 47% who returned for a follow-up serology test, the seroreversion rate was 39.5% and the seroconversion rate was 2.2%. The incidence of reinfection in the seropositive group was zero. Conclusion Although there is a decline in the IgG antibody signal over time, 60.5% of the seropositive HCWs maintain their seroconversion status after a median time of 5.5 months.