ABSTRACT
Background: Health care workers (HCWs) remain disproportionately affected by COVID-19. They experience higher transmission rates of SARS-CoV-2, and the extent, duration and pattern of antibody response remains under examined. The correlates of serological patterns are also unclear. We examined longitudinal SARS-CoV-2 sero-patterns and their correlates among a cohort of HCW. Methods: HCWs (N=465) were recruited at a large quaternary medical center in New York City and followed prospectively with bi-monthly assessments of the following;demographic characteristics, COVID-19 exposure in the work, home and community settings, and molecular and antibody COVID-19 laboratory tests including quantitative measurements of antibody titers. Baseline and longitudinal patterns in antibody response and titers over the first 4 months were used to characterize HCW who remained persistently seronegative, seropositive, those who acquired and lost seropositvity and those with variable seropositivity. Chi-square test for the association of seropattern correlates and loess regression was used to examine longitudinal trends. Results: Baseline seropositivity was 32.6% (N=148/465), 34.6% (N=153/441) at month 2 and 38.3% (N=125/326) by month 4. Exactly 63.9%, 27.3%, 1.5%, 1.5% and 5.7% of HCW tested overall were persistently seronegative, persistently seropositive, became positive after baseline, lost seropositivity and had variable positivity, respectively. Among seropositive HCW, mean antibody levels increased from 53.7 at baseline to 69.8 at month 2 and 82.9 at month 4 (figure 1). Factors significantly associated with being ever seropositive were, history of prior COVID-19 testing, household member testing COVID-19 positive, whether there were other essential employees in the home, and history or current symptoms. We also observed an association with contact of suspected or confirmed co-worker as significantly higher among HCW who were persistently positive (24.5%), incident seropositives (33.3%) and variable seropositivity (52.2%) than those who were persistently negative (19.9%) or lost seropositivity (16.7%). Conclusion: HCWs exposure risks continue to persist in the workplace and in the home. We observed few positive molecular tests, suggesting few transmission, but these exposure may potentially sustain seropositivity. These findings are preliminary and need to be further investigated.