The fifth sero survey by the Brihanmumbai Municipal Corporation (BMC) in Mumbai, conducted in the month of August, has shown that 86.64% of the 8,674 people surveyed have COVID antibodies. 

The latest sero survey noted a sero positivity of 87.02% in slums and 86.22% in non-slum areas. This is the first time that a modest difference in the sero positivity has been noted in the slum and non-slum population in Mumbai. The sero survey done in March 2021 had noted a sero positivity of 41.6% in slums and 28.5% in the non-slum population.

The present sero-surveillance was done from August 12 to September 8 this year and included the vaccinated population also. The sero-prevalence among the partially and fully vaccinated individuals has been found to be 90.26%, while among the unvaccinated individuals, the sero-prevalence is 79.86%... (The Indian Express, September 18, 2021)