Double vaccinate against Covid first, experts say amid calls for booster shots

New Delhi: India should prioritise double vaccinating its eligible population against Covid over booster shots given a large number of people still to get the base layer of protection against the infection, opine scientists.

Concerns over the Omicron variant and waning vaccine-induced protection against the infection have highlighted the need for boosters to protect the most vulnerable. And while many countries have already started giving booster shots, several experts here said the priority in India has to be different given that large-scale immunisation programme began only six-eight months ago.

In advocating putting boosters on the back-burner for the moment, the experts' opinion runs counter to the Indian SARS-CoV-2 Genomics Sequencing Consortium (INSACOG) that has recommended a booster dose for those above 40 years in high-risk and high-exposure populations.

The INSACOG is a network of national testing labs set up by the government to monitor genomic variations of COVID-19.

"We have a large proportion of our population in the below 18 age-group. Until that is achieved, a uniform policy for second booster, or a third dose, is not advisable," immunologist Vineeta Bal said, pointing out that large-scale vaccination in India began only in March 2021.

"What we should focus on," she said, "is fully vaccinating all the eligible population in India and pushing for vaccination of the under 18 age group on a large scale." 

Consistent finding with breakthrough infections is that these episodes are less in severity as compared to unvaccinated. That still confirms that immunity does exist in vaccinated individuals in India, said Bal, guest faculty at Pune's Indian Institute of Science Education and Research.

Satyajit Rath, from New Delhi's National Institute of Immunology (NII), added that it is not clear yet if boosters are needed for any vaccine worldwide yet.

"The duration of immune responses and protection are beginning to show differences, too, in recent studies. So I would be loath to jump the gun and say anything very definitive about boosters based on these data," he told a national news agency.

Bal agreed that there is no solid data on waning immunity in India. In principle, of course, immunity will wane with time.

Antibody levels in serum will be lower six months down the road than soon after vaccination but that is not the only and adequate evidence of significant lowering of protective immunity which is based on immunological memory, she added.

Vasant Nagvekar, a consultant on infectious diseases at a Mumbai-based hospital and a member of the Maharashtra government's COVID-19 task force on Thursday, said a booster dose of vaccine, even if it works, is just a temporary fix and the emphasis should instead be on mask use.

"Scientific data has proven that masks can reduce COVID-91 transmission by 53 per cent... A booster dose of vaccine, even if it works, is just a temporary fix. We can't keep on taking boosters every six months and for every variant of concern that emerges. Masking is the need of the hour and there is no Alternative for vaccination," he said in a statement.

Pune-based Serum Institute of India, which manufactures Covishield, on Thursday sought approval from India's drug regulator for a booster dose, citing adequate stock of the vaccine in the country and a demand for a third shot due to the emergence of new Coronavirus variants.

The government in a press briefing has said scientific reasoning for booster vaccine doses for COVID-19 is under examination but the priority is to ensure complete vaccination of the eligible population with both doses.