62% TN people have Covid antibodies: serosurvey

A statewide cross-sectional serosurvey on 26,610 samples conducted in July revealed that at least 62.2 per cent of the state’s population has developed antibodies to Covid-19 infection.

The highest seropositivity of 84% was observed in Virudhunagar district, south of Madurai, and the lowest was reported in Erode district (37%), near Coimbatore, according to results of the survey released by Tamil Nadu Health Minister Ma Subramanian on Saturday.

Among total samples, 17,624 individuals had IgG antibodies against SARS-CoV-2 cirus, according to the study, conducted by the Directorate of Public Health and Preventive Medicine in 888 clusters across the state.

In earlier state-wide surveys, the seropositivity was 31% in October-November last year, and 29% in the second phase of the survey held in April this year.

The latest survey, which was the third phase and conducted during the declining phase of the second wave of Covid-19 pandemic in Tamil Nadu, says, “intense vaccination drives across the state since January 16 and inclusion of 18+ age individuals for vaccination would have generated Protective Antibodies in the population.”

As on June 10, total number of people who were vaccinated — either single dose or both doses — in the state was 97.6 lakh.

According to the survey’s results, industrial belts in western Tamil Nadu such as Erode, Coimbatore and Tiruppur regions have reported around 45% seropositivity. This outcome was attributed to the consistent reporting of new cases in these regions. Of 3,690 samples from 123 clusters in Chennai district surveyed, seropositivity was found at 82%.