Thanks to immunity gained, 3rd wave may not be as severe as second one: ICMR study

The intensity of Covid-19 third wave may not be as severe as the second one as immunity attained during the earlier waves would be offering some protection against the new variant even if there is more transmissibility in the next wave, said Samiran Panda, senior scientist at the Indian Council of Medical Research (ICMR) on Saturday.

Panda has been part of an ICMR team which together with a collaborator from Imperial College London carried out a simulation study on the potential third wave, which was published online in the Indian Journal of Medical Research .

According to him, the key to controlling the third wave is to vaccinate the maximum number of people in the shortest possible time which may help flatten the curve.

The study sees the second wave prolonging till November and expects the third wave to emerge subsequently. It says that the third wave may be triggered by one or more of these four scenarios — waning immunity in people who were previously affected, emergence of a new virus variant capable of escaping pre-existing immunity, arrival of a more transmissible new variant and haphazard relaxation of lockdowns.

Less intense

Apart from Panda, who heads ICMR’s Infectious Disease Unit, ICMR chief Balram Bhargava, too, was among the authors of the paper. The study suggested that a third wave, if it would occur, is unlikely to be as severe as the second wave, given the extent of spread that has already taken place.

“A major reason for this model behaviour is that, given the explosive spread of infection across the country, a substantial proportion of the population is likely to have been exposed by the end of the current second wave, accounting for the effect of lockdowns,” the study said.

“Consequently, for a virus to cause a major third wave in the face of this pre-existing immunity, extreme scenarios for the abrogation of that immunity are required, or for that matter, for the transmission fitness of any novel virus,” it added.

However, the north-eastern States, which went in for early lockdown taking lessons from Delhi and Maharashtra, have a vast majority of their population vulnerable to the third wave and it is crucial for the government to ramp up vaccination drive in these States. “If the State-level restriction is lifted in north-eastern States, there is a possibility that the infection spread may go upwards again, so it is very important to step up vaccination drive in these States before they do the unlocking,” Panda said.

He said, currently the pace of inoculation has gone up and it is going very well for those in the high priority group like elderly population, people with co-morbidities, healthcare and frontline workers. And the study has clearly shown the criticality of vaccinating those in the north-eastern states to prevent the re-emergence of infections when the restrictions are eased, he further added.

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