Ninety-two per cent of deaths during India’s third Covid-19 wave have occurred among unvaccinated patients, health officials said on Thursday, releasing fresh data that they say show how vaccine acceptance and coverage helped blunt omicron’s impact.

Unvaccinated individuals were at greater risk of severe disease and death and have accounted for 92 per cent of Covid-19 deaths during 2022, said Balram Bhargava, director-general of the Indian Council of Medical Research, the country’s apex health research agency.

“India has experienced a considerably lower number of cases and a considerably lower number of deaths (than other countries) during the omicron surge,” said Bhargava, while outlining the results of an exercise to measure the impact of India’s vaccination campaign that has so far fully inoculated 82 per cent of adults.

The six-week-long third wave from early-January to mid-February this year at its peak had 337,000 daily new cases, compared with 414,000 daily new cases during the peak of the second wave during early May last year.

Medical experts have attributed the fewer cases and deaths under omicron to protection from immune responses generated by vaccines or prior Covid-19 infection and to omicron’s lower capacity to cause severe disease compared to delta, the variant that fuelled the second wave.

Both Covishield and Covaxin have helped protect people from severe disease or death during the omicron wave even though antibodies generated by the two vaccines have shown over 20-fold reduced capacity to neutralise omicron.

Laboratory studies have found that Covaxin-induced antibodies had 23-fold reduction and Covishield-induced antibodies 24-fold reduction in neutralisation capacity against omicron compared with three-fold and four-fold reduction against the delta variant, the ICMR chief said.

Those findings would imply that even vaccinated people would be susceptible to becoming infected. But experts say that other arms of the immune system activated by the vaccines and the immune responses from prior infections would have helped curb infections, severe disease and deaths.

The ICMR analysis, based on data from over 739 million fully vaccinated people and 50 million unvaccinated people, has suggested that full vaccination has 99.3 per cent effectiveness in preventing deaths from Covid-19.

“It is evident that vaccination coverage has played an important role in protecting lives in the recent surge,” said Vinod Paul, chair of the national expert group on Covid-19 vaccine administration and member (health) at Niti Aayog, the Centre’s apex think tank.

Health authorities on Thursday recorded 6,561 new Covid-19 cases amid continued signals of a steadily shrinking epidemic that has prompted the Centre and states to encourage normal economic activities alongside Covid-19 precautions.The case fatality rate (deaths among lab-confirmed cases) has been 0.35 per cent during the third wave compared with 1.29 per cent during the second, even taking into account the addition of earlier deaths by states through auditing exercises, a health official said.

India lost around 27,000 people to Covid-19 during the six-week-long third surge this year compared with over 252,000 during the 16-week-long second wave from mid-March through mid-July last year. The country’s official death toll is over 510,000, although several studies have suggested that the actual count of deaths could exceed three million.