CHENNAI, May 6 (WNM/Johns Hopkins Center for Health Security) - As India begins to relax nationwide “lockdown” measures in some parts of the country, in the midst of recent increases in reported COVID-19 incidence, health officials identified an outbreak associated with one of the “largest fruit and vegetable markets” in Asia (https://abcnews.go.com/Health/wireStory/virus-outbreak-india-market-cases-snowball-70528922). The Koyambedu market is located in Chennai (Tamil Nadu state), and the outbreak has been linked to more than 500 cases in Tamil Nadu and Kerala states. Notably, the number of active cases reported in Tamil Nadu has more than tripled over the past 8 days, increasing from 812 cases on April 28 to 2,540 on May 6.
The market reportedly continued to operate during India’s nationwide “lockdown,” as it is a critical component of the regional food supply; however, the use of face masks, PPE, and hand sanitizer was reportedly not widely implemented at the market. According to a report published by ABC News, thousands of local residents “rushed to the market” in late April to stockpile food after the Tamil Nadu government announced a “four-day ‘intensified’ lockdown,” which could have resulted in mass exposure to the virus. The first case associated with the market was not detected until 3 days later. Individuals exposed that day could still be in their incubation period or potentially already infectious and transmitting the infection to others.
The market is currently closed, but public health responders are struggling to trace contacts and identify associated cases, in particular because affected individuals may be reluctant to come forward due to concerns about “stigma or quarantines.” An inability to identify and isolate/quarantine new cases and exposed individuals could lead to further transmission. This outbreak illustrates that community transmission was occurring in some parts of India prior to cases being detected, even during the “lockdown.” As India begins to relax social distancing, it is critical to expand testing and surveillance capacity, including outside of “hotspot” areas. Otherwise, large-scale community transmission can go unnoticed, which can risk sparking a larger epidemic and necessitate further restrictions.