A study of 614 fully vaccinated health workers in India found a “significant” drop in their anti-COVID antibodies within four months of the first shot. The results could help the government decide whether to provide booster doses like some Western countries have done.
The decrease in antibodies does not necessarily mean that immune people lose their ability to fight disease, because the body’s memory cells can still kick in to provide substantial protection, said the director of a public institute that has conducted the study.
“After six months, we should be able to tell you more clearly if and when a booster would be needed,” Sanghamitra Pati of the Bhubaneswar-based Regional Medical Research Center told Reuters on Tuesday. “And we would advocate similar studies in different areas for pan-Indian data.”
British researchers said last month that the protection offered by two doses of the Pfizer / BioNTech and AstraZeneca vaccines starts to wear off within six months.
The study, published on the Research Square pre-print platform but has not yet been peer-reviewed, is one of the first to be carried out in the country regarding its two main vaccines – Covishield, a version under license of the vaccine AstraZeneca, and Covaxin developed at the national level.
Health officials say that while they are studying the evolution of science on booster doses, the priority is to fully immunize the 944 million Indian adults. More than 60% of them received at least one dose and 19% received the two required doses.
Covid cases and deaths in India have fallen sharply from a peak of more than 400,000 infections in early May. India has reported a total of 33.29 million cases and 443,213 deaths.