SARS-CoV-2 Seroprevalence Among Healthcare Workers by Workplace Exposure Risk in Kashmir, India.

Background: SARS-CoV-2 infection (COVID-19) poses a tremendous challenge to healthcare systems across the globe. Serologic testing for SARS-CoV-2 infection in healthcare workers (HCWs) may quantify the rate of clinically significant exposure in an institutional setting and identify those HCWs who are at greatest risk.

Methods: We conducted a survey and SARS-CoV-2 serologic testing among a convenience sample of HCWs from 79 non-COVID and 3 dedicated COVID hospitals in District Srinagar of Kashmir, India. In addition to testing for the presence of SARS-CoV-2-specific immunoglobulin G (IgG), we collected information on demographics, occupational group, influenza-like illness (ILI) symptoms, nasopharyngeal reverse transcription polymerase chain reaction (RT-PCR) testing status, history of close unprotected contacts, and quarantine/travel history.

Results: Of 7,346 eligible HCWs, 2,915 (39.7%) participated in the study. The overall prevalence of SARS-CoV-2-specific IgG antibodies was 2.5% (95% CI, 2.0%-3.1%), while HCWs who had ever worked at a dedicated COVID-19 hospital had a substantially lower seroprevalence of 0.6% (95% CI, 0.2%-1.9%). Higher seroprevalence rates were observed among HCWs who reported a recent ILI (12.2%), a positive RT-PCR (27.6%), a history of being put under quarantine (4.9%), and a history of close unprotected contact with a person with COVID-19 (4.4%). Healthcare workers who ever worked at a dedicated COVID-19 hospital had a lower multivariate-adjusted risk of seropositivity (odds ratio, 0.21; 95% CI, 0.06-0.66).

Conclusions: Our investigation suggests that infection-control practices, including a compliance-maximizing buddy system, are valuable and effective in preventing infection within a high-risk clinical setting. Universal masking, mandatory testing of patients, and residential dormitories for HCWs at COVID-19-dedicated hospitals is an effective multifaceted approach to infection control. Moreover, given that many infections among HCWs are community-acquired, it is likely that the vigilant practices in these hospitals will have spillover effects, creating ingrained behaviors that will continue outside the hospital setting.