Seroprevalence of COVID-19 Amongst Health Care Workers in a Tertiary Care Hospital of a Metropolitan City from India.

Background: Seroprevalence studies for COVID-19 evaluate the extent of undetected transmission in a defined community, with special significance among health care workers (HCW) owing to their greater exposure and potential to transmit.

Methods: A total of 1122 HCW (approximately 25% of the employees) of a large tertiary care hospital in India were recruited for this cross-sectional study. COVID PCR-positive HCW were excluded. Based on their risk-assessment, participants were grouped into three categories. A questionnaire was administered and they were tested for SARS-CoV-2-IgG antibodies using the chemiluminescence.

Results: The overall seroprevalence among workers was 11.94%, which included 19.85% in COVID units, 11.09% in non-COVID units, and 8% in administrative workers (p=0.007). Antibody prevalence was highest in the department of gastroenterology (11.94%), followed by oncology (10.53%), pathology (10.26%), emergency medicine (7.84%) and critical care medicine (7%). Housekeeping staff, food and beverage staff, lab assistants and technicians had higher seroprevalence rate than doctors and nurses (p < 0.0001). HCW with a history of BCG vaccination in childhood and those who received an adequate prophylactic dose of hydroxychloroquine (HCQ) had a lower seroprevalence as compared to those who did not (7.31% vs. 16.8% and 1.30% vs. 11.25% respectively).

Conclusion: BCG vaccination, HCQ prophylaxis, and the job profile influence the seroprevalence rate in HCW. Seroprevalence rate and follow-up evaluation of its durability may help hospitals to triage their staff at risk, rationalize their placement, prioritize the use of PPE, thereby potentially reducing the risk.