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

Papasavas, Pavlos; Olugbile, Sope; Wu, Ulysses; Robinson, Kenneth; Roberts, Amity L.; O’Sullivan, David M.; McLaughlin, Tara; Mather, Jeffrey F.; Steinberg, Adam C.; Orlando, Rocco; Kumar, Ajay

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.