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87 percent of people of TN have antibodies to Covid, Study

- February 10, 2022

Chennai, Feb 10 (BPNS)

The fourth phase of the Sero surveillance study conducted by the Tamil Nadu health department has revealed that around 87 percent of people tested in the state have anti-bodies to Covid. The cross-sectional survey was conducted in December 2021 at the beginning of the Omicron variant triggered the third wave.

It may be noted that in the third phase of the sero-surveillance survey, 70 percent of the people tested had antibodies.

The state health minister Ma Subramanian in a statement on Wednesday said that Tiruvarur district had the highest seropositivity rate of 93 percent in the state. The seropositivity of Chennai was 88 percent, according to the minister.  The statement said that in four districts of the state seropositivity rate was below 85 percent. Tirupathur (82%), Kancheepuram (83%), Villupuram and Dharmapuri (84%).

Of the 32,245 people tested for the survey, 27,324 (85%) were vaccinated and among them, 24,667 (90% ) had detectable levels of anti-SARS-CoV-2 IgG antibodies.

Interestingly, the statement said that of the 4921 unvaccinated people tested as part of the study, 3374 (69%) had developed antibodies.

The study highlighted that vaccinated people have better detectable antibody levels. Among those who took Covaxin or Covishield, more than 80 percent had antibodies. The study also found that 68 percent of unvaccinated people aged 11-18 had detectable levels of antibodies. The health department said that this was evidence of indirect exposure to natural infection.

Tamil Nadu health minister Ma Subramanian while speaking to BPNS said, “ The state public health department has taken samples from people above the age of 10 years from 1076 clusters across all districts of the state and found that at an average 87 percent have developed antibodies and this is a good sign.”

He said that each cluster had 30 persons drawn randomly from the community and said that district collectors were told to increase the vaccination coverage in districts with a seropositivity rate below 84 percent. Thirupathur with 82 %, Kancheepuram with 83%, and Villupuram and Dharmapuri with 84% fall under this category, the minister said.

Meanwhile, the whole genome sequencing conducted on January 26th found that 97 percent of samples were Omicron variant while only 3 percent was Delta variant of the Covid -19 virus.

Interestingly on December 7, all samples were Delta and on December 11, 87 percent was Delta while 13% were of Omicron variant.

The Tamil Nadu health minister said that the first dose vaccination coverage for children in the age group of 15-18 is 80.48 percent while the second dose coverage is 22.13 percent. He also said that only four percent of active cases are admitted in hospitals across the state.