Seroprevalence of SARS-CoV-2 infection among frontline police personnel in Mumbai, India

INTRODUCTION: A serosurvey was designed to ascertain the extent of infection among police personnel in Mumbai, India, during the last week of January 2021, at the end of the first wave of the COVID-19 pandemic, and just before the introduction of vaccination. METHODS: The survey was carried out to screen for SARS-CoV-2 among 3232 police personnel. Of the 3176 participants willing for blood sample collection, 3077 personnel were found to be eligible for testing antibodies against the SARS-CoV-2 virus using the Roche Diagnostics’ Elecsys Anti-SARS-CoV-2 assay. RESULTS: The overall seroprevalence was 74.1% (95% CI 72.5–75.6). Males (75.1%, 73.4–76.8) had significantly higher seroprevalence than females (69.8%, 66.0-73.3), 18–39 years age group (76.4%, 74.4–78.3) than 40–59 years age group (70.6%, 67.9–73.1), non-officers (75.2%, 73.5–76.7) than officers (63.8%, 58.2–69.0), and personnel without comorbidities (75.0%, 73.3–76.6) than with comorbidities (69.7%, 65.6–73.5). Additionally, personnel with resident members positive for COVID-19 (89.6%, 84.7–93.1), personnel having reported COVID-19 earlier (95.5%, 93.8–96.7), and personnel having PCR positivity earlier (96.4%, 94.7–97.6) had significantly higher seroprevalences than others. All other variables, including diabetes and blood glucose status, lipid levels and thyroid enzymes, were not significantly associated with the seroprevalence levels. CONCLUSIONS: Almost three-fourths of frontline police personnel had evidence of past COVID-19 infection at the end of the first wave in January 2021, just before the introduction of COVID-19 vaccination. These frontline non-healthcare essential workers are an important risk group, and amenable to rapid serosurveys. These findings may help in estimating transmission status in the general community, along with disease burden, aiding prioritization of healthcare services.