Resource centre on India's rural distress

ICMR unlikely to commission new serosurvey -Jacob Koshy

-The Hindu

Vaccination drive likely to throw up erroneous inferences, experts

The Indian Council of Medical Research (ICMR) is unlikely to immediately undertake a fourth national serology survey to estimate the extent of exposure to the coronavirus since January. Officials told The Hindu that though discussions were still on, undertaking such a study presented newer logistical challenges and the ongoing vaccination drive could read to erroneous inferences.

The ICMR has conducted three national serology surveys since May 2020 and found that the exposure to the virus was much higher than that was reported by confirmed cases. The third serosurvey that measured the spread of infection between August and December found that 21% of India's adult population and 25% of those in the 10-17 age group may have been infected.

However, India's devastating second wave began around mid-March amidst a vaccination programme that prioritised healthcare, frontline workers and senior citizens.

Serology surveys take blood samples from participants and measure antibodies to check past exposure to the virus. However, because vaccinations also trigger an antibody response after two weeks, they could be misleading. “Serosurveys lose their scientific relevance once vaccination starts in the population,” Dr Balram Bhargava, Director General, ICMR told The Hindu.

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