Top vaccine experts told Mint that there is no urgency to narrow the nine-month gap between the second dose of the COVID-19 vaccine and the booster shot and that India has enough local data to guide any such decision. There is no further evidence.
Furthermore, rising Covid-19 infections should not force a knee-jerk reaction to bridge the gap, several scientists said.
Only over 10% of adults have completed the nine-month period to become eligible for a booster. If the nine-month gap persists, only 35% will be eligible for a booster by the end of July, potentially leaving some less protected as immunity wanes, show Mint counts.
However, India does not have much data to support a six-month lag over a nine-month gap, experts said. Epidemiologist Chandrakant Laharia said, “There is no evidence to argue for or against nine months. In India, there is no evidence on the ideal difference, so any interval would be equally wrong or right.”
Earlier this week, a study from the National Institute of Virology found that antibodies begin to drop six months after vaccination or infection, making for a shorter interval of time. Citing sources, PTI reported this week that the Center may soon reduce the gap to six months after the expert group meeting on Friday.
The World Health Organization says a booster “may be considered” four to six months after the second dose of the Oxford-AstraZeneca vaccine, and is “primarily recommended” for high-priority groups. With COVID-19 reaching an endemic stage in India, some feel the risk is low. “At the moment, given our infection rates and vaccinations, I’m not worried enough about the numbers to replace any recommendations—with the reminder that I don’t know how the nine months were decided,” said a top virologist. Gagandeep Kang told Mint. ,
see full image
Former Professor of Clinical Virology at Christian Medical College, Vellore, T. Jacob John said small gaps during high diffusion periods such as delta wave and omicron wave were relevant to protect high-risk individuals, but India has reached endemic people. phase since then. “Nine versus six months are irrelevant now. The need for boosters is a thing of the past,” he said. However, he added that a booster is necessary to complete the vaccination programme.
If the gap is six months, 34% of adults will become eligible immediately. With a sudden surge in demand, the concomitant infrastructure will need to be restored quickly. According to Mint calculations, the average number of vaccination sites walked per day has jumped from a January peak to about 46,000 this month, as demand eases. The two-dose campaign is nearing its end with nearly 91% of adults being vaccinated.
Going forward, experts called for clarity about the purpose of the booster shot to agree on a time frame along with concrete data on declining safety in the Indian context. Laharia said, “We need to agree on the objective (to fix the interval). Is the booster being given to reduce transmission or to protect against moderate to severe disease? If it’s the latter, then the booster can wait.” Kang said it was important to first consider who we want to protect and whom—infection, hospitalization, or death—rather than making blanket recommendations.