JOIN USTamil Nadu Serosurvey finds Covid antibodies in 66% population
The seropositivity rate in Tamil Nadu stands at 66.2 per cent, the third serosurvey conducted by the Department of Public Health has revealed. The seropositivity rate of 66.2 per cent is much higher than 29 per cent in March-April this year and 31 per cent recorded in October-November last year.
The survey by the DPH was conducted between the last week of June and July this year when the second wave of Covid-19 infections was on a decline in the state. Virudhunagar district in southern Tamil Nadu and Chennai, the capital city, bagged the first two places with a seropositivity range of 84 per cent and 82 per cent respectively.
Of the 26,110 samples tested during the serosurvey, as many as 17, 624 individuals had IgG antibodies for the SARS-CoV-2 virus that causes Covid-19 infection. The overall seropositivity rate was 66.2 per cent which could be attributed to the expanding vaccination coverage among other reasons.
While Chennai has conducted two separate surveys, this is the third serosurvey that has covered the entire state. Of the 38 districts, only five districts have less than 50 per cent of seropositivity rate while the remaining are above the mark.
The western region comprising seven districts have recorded some of the lowest positivity rates. While Salem has recorded 60 per cent, Erode 937 per cent), Coimbatore (43 per cent), Tiruppur (46 per cent), Namakkal (48 per cent), Karur (51 per cent), and Nilgiris (55 per cent).
“Intense vaccination drives across the state since January 16, 2021, and inclusion of 18+ individuals for vaccination would have generated Protective Antibodies in the population,” the serosurvey said. As per figures released by the Health Department, as many as 2.29 crore Covid-19 doses have been administered in the state of which 15.30 lakh are from the private sector.
About the low seroprevalence rate in western districts, the survey attributed it to the “consistent reporting” of new Covid-19 cases in the region. “Serosurveys are very important in any pandemic. It is a very critical tool in finding the prevalence of antibodies for the virus. Serosurveys help the authorities plan their next course of action. If a serosurvey says 80 per cent of the total population have antibodies, then the impact even in the case of a third wave would be very less,” a public health expert who advises the Tamil Nadu Government told DH.
While the first survey was conducted between October and November 2020, the second one was carried out between March and April 2021.