Sero-surveillance provides estimates of antibody levels against infectious diseases and is considered the gold standard for measuring population immunity due to past infection or vaccination. Such studies are crucial to make informed public health policy decisions and control disease transmission. 

The Mumbai SARS CoV-2 seroprevalence study aimed to provide information about exposure to infection, progression of the disease, and how socioeconomic disparities and population density might drive disease dynamics in megacities. The data can be used to help public health professionals, policy makers and health care providers to monitor the spread of COVID-19 and support better understanding of illness, disease severity and effectiveness of community interventions.

In three wards of Mumbai, over 12,000 residents of slums and non-slum areas were randomly selected to participate in either round of the survey. In the first round, conducted in June and July 2020, we found a seroprevalence of 56.5% in slums and 15.5% in non-slum areas. In the second round of testing conducted in August 2020, we found a seroprevalence of 45.2% in slums and 17.1% in non-slum areas. 

The study was conducted by TIFR, THSTI, Kasturba Hospital, ATECF and IDFC under the aegis of NITI-Aayog (GoI) and the MCGM.