About 34% of TN may still be vulnerable to Covid: Serosurvey

A total of 888 clusters were covered for the survey, and each cluster consisted of 30 participants, drawn randomly from a rural area or an urban neighbourhood.

Published: 01st August 2021 03:41 AM  |   Last Updated: 01st August 2021 03:41 AM   |  A+A-

Pregnant women getting vaccinated at Egmore Children’s Hospital in Chennai on Monday | R Satish Babu

Express News Service

CHENNAI: According to the results of the third serosurvey conducted by the TN Health Department, as many as 17,624 of the 26,610 samples taken, to check for the presence of Immunoglobulin G (IgG) antibodies against the coronavirus, have tested positive. In other words, about 66.2 per cent of people in TN have the presence of these antibodies, which means that 33.8 per cent people may still be vulnerable to the virus.

A total of 888 clusters were covered for the survey, and each cluster consisted of 30 participants, drawn randomly from a rural area or an urban neighbourhood. The highest seropositivity, or the presence of antibodies, was observed in Virudhunagar district with 84 per cent of people testing positive, followed by Chennai with 82 per cent. The least seropositivity was found in Erode and Coimbatore districts, recording 37 and 43 per cent, respectively.

While 31 per cent seropositivity was recorded in the first survey, taken in October 2020, it had reduced to 29 per cent during the second such survey in April this year. The latest report stated that the 66.2 per cent seropositivity could be attributed to the timing of the survey as it was done immediately after the second wave. Meanwhile, new cases rose for the third consecutive day from 1,947 on Friday to 1,986 on Saturday.

Prevalence of antibodies due to intense vax drive: Survey

The intense vaccination drive against Covid-19 across the State and the inclusion of people aged above 18 years in the drive, would have generated protective antibodies in the population, the serosurvey highlighted.

Health experts opined that this result may not mean much in a densely-populated State or country. “In less populated countries, it may mean a lot. But in TN, this means that at least two crore people may still be susceptible to the virus,” said Dr K Kolandasamy, former Director of Public Health. However, he added that this may be a good sign about the vaccination coverage and testing of newer cases. “This also can be a necessary data for schools to reopen in the State. Authorities can now look up cluster-wise data and vaccinate all parents of higher secondary students, and then reopen schools,” he said.

Meanwhile, Health Secretary Dr J Radhakrishnan reiterated that people must not let their guards down yet. “Antibody levels may be high today, but it may taper down tomorrow,” he said, adding that there seems to be a casual attitude creeping up among people in recent times. “In parallel, we are also doing genomic sequencing to check the fresh cases. Whenever there is a cluster, we do genomic sequencing to identify if newer variants are present,” said the secretary.


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