Since the time the pandemic broke out in the country, Maharashtra has remained the worst-hit state due to COVID. A third sero survey is underway to estimate the proportion of Mumbai residents infected by Covid-19 in the past year. “We are in the process of collecting 500 samples from each of the 24 wards,” said BMC additional municipal commissioner Suresh Kakani. The survey started on March 1 and should be completed within another 7-10 days.

“We decided to carry out the third sero survey to understand the level of antibodies in the population. The information will help us decide on our future Covid vaccination policy,” said Kakani.

In 2020, the BMC conducted two sero surveys in three municipal wards —F North (Matunga), R North (Dahisar) and M West (Chembur) —in July and August 2020. The surveys revealed the city’s dense slums pockets had higher proportion of people with antibodies as compared to people living in buildings. The July survey found that 57% of the slum residents and 16% of the building residents had antibodies, and the corresponding numbers for August were 45% and 18% respectively.

While the earlier two sero prevalence surveys collected around 6,000 samples each, the target for the third survey is 12,000 samples.The earlier surveys were a joint effort of BMC, Niti Aayog and the Tata Institute of Fundamental Research (TIFR), while the municipal corporation is doing the present survey on its own. BMC’s deputy executive health officer Dr Daksha Shah and Nair Hospital’s head of microbiology Dr Jayanti Shastri are part of the special civic team handling the third survey.