70% population in Tamil Nadu has antibodies against COVID-19, reveals serosurvey

The highest seropositivty was reflected in Virudhunagar district (84%), whereas Chennai, Madurai, and Theni districts reported over 75% seropositivity.

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Chennai: In its latest and third serosurvey, the Tamil Nadu Government has revealed that 17,090 individuals of 24,586 had developed antibodies against COVID-19, which amounted to 70%. 

This survey was conducted between the months of July and August, under the supervision of the State Director of Public Health and Preventive Medicine, by taking samples at random from 30 persons in an urban street or a village. The presence of antibodies in the bloodstream shows that a person has either been infected with COVID-19 and developed antibodies to fight the virus or that the effect of vaccination is reflecting. 

As with the previous survey that was conducted in July 2021, the highest seropositivty as reflected in Virudhunagar district (84%), whereas Chennai, Madurai, and Theni districts reported over 75% seropositivity. Notably, Karur district had the lowest seropositivity of 51%. Districts such as Perambalur, Ariyalur and Nilgiris also reported a rate of less than 60%. 

According to the Government, this survey was conducted across 827 clusters (30 randomly picked individuals) that were spread across cities and rural areas. Their blood samples were collected and tested for the presence of SARS CoV-2 IgG antibodies using Chemiluminescence based Immune Assay (CLIA), at six referral labs of the government. 

In recent weeks, the Tamil Nadu Government has also been conducting mega vaccination drives on Sundays, with the aim of inoculating over 20 lakh persons every Sunday.