One in every five person living in Chennai is estimated to have had contracted Covid-19, a new population-based sero survey for the transmission of coronavirus in Chennai has found.

The survey was carried out as part of the national Covid sero survey.

The survey found that overall, one-fifth of Chennai's population was exposed to Covid-19. However, the survey shows huge variation in seroprevalence across different zones in the city, indicating different levels of transmission.

Blood samples of 12,405 people from 51 wards covering 15 zones were collected for this survey. Of these 12,405 samples, 2,673 individuals had evidence of past SARS CoV 2 infection, the survey found.