One in three people in Chennai developed COVID-19 antibodies, says sero survey

At a time when Chennai’s daily COVID-19 cases are dipping below the 1000-mark consistently, the findings of the second serosurvey has revealed that 32.3% of the city’s population has developed IgG anti-bodies to Covid-19. As per the Chennai Corporation, 6389 samples were collected on a random basis from streets and households across the city, of which 2062 tested positive for IgG anti-bodies.

Population-based serosurveys are performed to measure the spread of infection in the community. Such surveys are done by performing blood tests on individuals to check if they have developed antibodies to an infection. The second serosurvey was started on October 8th and the detailed results with ward-wise figures and findings are awaited. An official told Zee media that the results would be available in a couple of days and that the methodology of the survey was similar to the earlier one.

An earlier serosurvey conducted by the government authorities in between mid-July and early-August has indicated that one-fifth of Chennai’s population has been exposed to the SARS-CoV-2 infection. SARS-CoV-2 is the virus that causes the disease - Covid-19. The study which was conducted by the National Institute of Epeidemiology of the Indian Council of Medical Research and the Greater Chennai Corporation was based on the analysis of blood samples from 12,405 individuals from all zones of the city.

The methodology adopted for the first survey involved collecting blood samples at random from individuals aged above 10, from the streets in the highly populated areas of the city. The field data collection is said to have happened between 18th and 28th July, whereas the testing the collected samples was completed by August 6th. 

On Wednesday, Tamil Nadu had recorded 3086 new cases and 39 deaths, with the total case count at 6,97,116. 4301 persons were discharged, thus taking the total number of recoveries to 6,50,856, a recovery rate of 93%.

As cases are decreasing steadily and the festive season is fast approaching, the Tamil Nadu government announced new relaxations to aid economic activity. The Chief Minister said that all shops, hotels, tea stalls, restaurants, commercial complexes located in non-containment zones can remain open till 10 pm onwards, effective from Thursday, 22nd October. However, he also emphasized the Covid-19 protocols be followed in a strict manner.