India’s apex vaccination policy group is this week set to discuss Covid-19 vaccine booster doses amid research suggesting that prioritising boosters for vulnerable populations now could reduce deaths by 5 per cent under omicron-fuelled waves.

The National Technical Advisory Group on Immunisation’s (NTAGI) meeting on boosters will come only days after an international research team calculated that prioritising the limited vaccine supplies for boosters for the elderly or high-risk groups would bring greater public health gains.

The team from the Imperial College, London, and other institutions has estimated that prioritising boosters for the elderly and high-risk groups ahead of an omicron wave would reduce deaths by an additional 5 per cent compared with using those doses on younger age groups.

A policy that prioritises boosters for such vulnerable populations over full vaccination for younger people would contradict India’s current policy of prioritising full vaccination for all adults first.

“Not introducing boosters now could mean 5 per cent excess deaths under an omicron wave,” said Shahid Jameel, a senior virologist and former head of the Wellcome Trust DBT India Alliance, a UK India research funding partnership, who was not associated with the Imperial College-led study.

“But this calculation is specifically for countries such as India that have had substantial prior Covid-19 infections — and it suggests there is a clear public health benefit of completing vaccination of at-risk populations fast and deploying boosters to them now,” Jameel said.

The projection is based on expectations of waning vaccine-induced antibodies and examines a worst-case scenario for populations with prior infections and vaccinations, he said.

The demand for booster doses has intensified in India with doctors and sections of public health experts citing concerns about waning immunity and growing evidence that boosters can help save the lives of the elderly, the immuno-compromised, and those with chronic health disorders.

The Indian Medical Association had earlier this month urged the Centre to announce boosters for healthcare workers, who were the first to receive the jabs when the country’s vaccination campaign started in January.

“In the interest of saving lives, we need a policy on boosters for at least the vulnerable population groups right away,” said Giridhar Babu, professor of epidemiology at the Indian Institute of Public Health, Bangalore. “There is clear and growing evidence that boosters are needed in high-risk groups.”

Health officials had last week asserted that India’s current policy of fully vaccinating all adults ahead of boosters was in line with the World Health Organisation’s recommendation to prioritise fully vaccinating eligible populations before introducing boosters.

India’s vaccination campaign had until Monday fully vaccinated around 554 million (58 per cent) of an estimated 944 million adults. But experts say vaccine-induced antibodies would have likely waned in recipients who had received their second doses more than seven months ago.

Health officials and researchers have underlined that the loss of vaccine-induced antibodies need not mean a loss of protection as other arms of the immune system, such as T-cells, may still help keep viral loads low and protect people from severe disease.

Some officials have speculated that immune responses resulting from prior Covid-19 infections, vaccinations or both would likely provide some protection from omicron when it sweeps across the country.

But experts say that this hope should not preclude India from introducing boosters while simultaneously adopting public health measures to detect and contain local surges and preparing hospital, oxygen and ventilator resources for bad scenarios.

“Overestimating lower virulence of omicron is unwarranted,” Babu tweeted on Monday. “It’s only helpful if (the) overall number of vulnerable getting infected remains low. Prioritising boosters and beds for all those at risk of hospitalisation is an important determinant of how well we (will) fight omicron in early 2022.”