Clamour for booster shots grows, but experts say it’s too early for India

A booster dose is given to those with waning double-dose immunity and may be the same or a different vaccine from the first two. Sixty-one countries, mostly rich ones, have given booster shots to at least 1% of their population, according to Our World in Data. Only 15 of them ramped up boosters before fully vaccinating half their population. The list includes countries that started with Sinovac, which has lower efficacy than other jabs. Booster shots are largely being prioritized for high-risk groups and those vaccinated early, while some high-income countries with excess supply are giving these shots even to the wider population. In India, both doses have reached only 34% of the population. Starting booster doses now would put India in a small club of six countries—Turkey, Thailand, Bolivia, Russia, Albania, and the Dominican Republic—that began booster shots early.

Primary immunization of all adults should continue to be prioritized, alongside research and data collection to answer questions that can help guide policy on booster doses, said epidemiologist Chandrakant Lahariya. “Booster doses may be needed in due course, but they should be based on an independent scientific decision, not because we reached a certain level of double-dose coverage or because surplus doses are lying unused,” he said.

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Some calls for booster doses, especially from the private sector, have emerged because unused doses are set to expire. “India is likely to have sufficient supply for quite some time,” Lahariya said. “But excess supply cannot be a criterion for booster shots. Unused supplies can be used in other ways: giving them free of cost, the government or manufacturers buying them back, or more exports.”

While booster shots are known to help make up for waning immunity, administering them so early would be a matter of ethics and fairness, said Ramanan Laxminarayan, director of the Center for Disease Dynamics, Economics and Policy. “Are we better off focusing on the unvaccinated or in boosting immunity in those already vaccinated?” he asked. “All priorities come at a cost, and it will be deeply unfortunate if the focus on the booster shots comes at the cost of vaccinating more of India’s population that remains at risk.”

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Bihar, Jharkhand, and Uttar Pradesh are yet to reach 25% double-dose coverage. The clamour around boosters has grown in recent weeks, with some states as well as Opposition parties raising the matter with the Centre. The Indian SARS-CoV-2 Genome Consortium (INSACOG), a group set up by the Centre, suggested that booster shots be “considered” for high-risk groups above 40—though the group later said it was not a recommendation and more studies were needed. Another government panel that met on Monday to discuss the possibility could not arrive at a decision. Health minister Mansukh Mandaviya told Parliament last week that a decision would be made based on experts’ advice.

Last month, the World Health Organization condemned the practice of rich countries giving boosters even when poor ones had hardly got started and called it a “scandal that must stop now”. The WHO says booster doses may only be needed “if there is evidence of insufficient protection” against severe disease, hospitalization, or death. There is no evidence yet on whether existing vaccines won’t protect against Omicron.

Epidemiologists point to India’s high natural immunity levels after the second covid-19 wave in April-May. “Every country’s context is different,” Lahariya said, calling for a research-based approach to decide on booster doses and selecting eligible groups. “Natural infection from second wave may work very similarly to a booster shot.”

The benefits of booster doses are unknown and unproven, at least for vaccines used in India, but the benefits of the first two doses are known, so that must be the priority for India, he added.