Even as governments in several countries are authorising a Covid-19 booster shot six months after completion of primary series, medical opinion is divided on the need for this. Experts with the World Health Organization have advised against boosters.

Dr Rajeev Jayadevan, who is a member of the National Task Force of IMA for Coronavirus pandemic, has, in a paper published in The Lancet this month, said, “caution must be exercised before endorsing widespread use of vaccines as third or fourth doses to millions of otherwise healthy people”.

Israel study

His contention is that there is insufficient evidence on effectiveness of a third dose. The Israel study which claimed effectiveness only had 12 days of follow up and is confounded by the lower rate of testing among those who took the third dose, he points out.

Speaking to BusinessLine , Jayadevan said what is driving the narrative for a booster dose is that antibodies in vaccinated people are dropping. However, he contends that immunology is so complex that a reliable range of antibodies cannot be gauged. It is natural for antibodies to drop after some time, but when re-challenged by the same agent, the body is instantly capable of regenerating antibodies, he says.

Yes, there have been breakthrough infections, he admits. But, awareness needs to be created that though the vaccine’s protection against infection is short-lived, its protection against death is long term, he says.

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