SARS-CoV-2 cluster among security guards, Chennai, Tamil Nadu, India, June-July 2020

Congregate work settings are at increased risk for SARS-CoV-2 transmission and predispose to super spreader events. We investigated a COVID-19 outbreak among security guards to identify the risk factors and propose recommendations. We defined a COVID-19 case as a laboratory-confirmed reverse transcription polymerase chain reaction-positive case. We traced the contacts actively and described the cases by time, place, and person. We conducted a case-control study and collected data on potential exposures. We identified 20 (27%) COVID-19 cases among 75 security guards. Among the cases, 17 (85%) were male and 12 (60%) were symptomatic. We recruited all the 20 COVID-19-confirmed cases and 55 COVID-19-negative controls for the case-control study. SARS-CoV-2 infection was higher among those had high-risk exposure (60%, [12/20]) than who did not (16%, [9/55], adjusted odds ratio = 5.9, 95% confidence interval = 1.6-22.1). Having had high-risk exposure with COVID-19 cases led to COVID-19 outbreak among the security guards. We recommended avoiding the activities predisposed to high-risk exposure.