The third Tamil Nadu Cross Sectional Serosurvey in July, covering 26,610 samples revealed that atleast 66.2 per cent of the population has developed antibodies to SARS-CoV-2. Among the 26,610 samples tested, 17,624 individuals had IgG (Immunoglobulin G) antibodies against SARS-CoV-2 virus.
The overall seropositivity of 66.2 percent could be attributed to variouspossible reasons, including the timing of serosurvey conductedduring the declining phase of the COVID second wave in TamilNadu, the report said. “Intense vaccination drives from
Each cluster consisted of 30 participants drawn randomly from a village in a rural area or a street in the case of an urban one. Blood samples were collected from a total of 26,610 participants and tested for the presence of SARS CoV-2 IgG antibodies using Chemiluminescence based Immuno Assay (CLIA).
All the samples were tested at six referral labs of DPH & PM located in Chennai, Tiruchy, Madurai, Coimbatore, Tirunelveli and Salem for the detection of IgG antibodies. Health Minister Ma Subramanian released the report in the presence of Health Secretary J Radhakrishnan and Director of Public Health and Preventive Medicine Dr TS Selvavinayagam. The serosurvey was successfully completed under the supervision of Selvavinayagam and his team at the state and district level.
In the earlier state-wide serosurveys conducted by DPH&PM, the seropositivity was 31 percent in October/ November 2020, and 29 percent (in the second conducted in April 2021).