3rd wave may hit its peak between Oct-Nov : Govt panel

July 5, 2021 32 Views No Comment

NEW DELHI, JUL 5 (AGENCIES) : A possible third wave of Covid-19 may hit its peak in October-November this year if Covid-appropriate behaviour is not followed, but it is likely to see half the number of daily cases that were recorded during the second surge, said a scientist of the government panel in charge of modelling Covid-19 cases.

However, if a new virulent variant of SARS-CoV-2 emerges, the infection will spread faster during the third wave, said scientist Manindra Agrawal.

He is part of the expert panel formed by the Department of Science and Technology last year to forecast the surge of coronavirus cases using mathematical models. Besides Agrawal, who is a professor at IIT-Kanpur, the panel also has M Vidyasagar, another scientist with IIT-Hyderabad, and Lt. Gen M. Kanitkar, Dy. Chief (Medical) of Integrated Defence Staff, as members.

The panel came up with the Sutra Model last year to mathematically project the trajectory of Covid-19 in India. They were criticised earlier this year for not having predicted the ferocity of the second wave of the pandemic.

Third wave predictions: On their predictions for the third wave, Agrawal said that loss of immunity, effects of vaccination and the possibility of a more virulent variant have been factored in this time, which was not done while modelling the second surge. A detailed report will be published soon.

In a series of tweets, Agrawal explained, “We have created three scenarios. One is optimistic, where we assume that life goes back to normal by August and there is no new mutant. Another is intermediate wherein we assume that vaccination is 20 per cent less effective in addition to optimistic scenario assumptions.

“The final one is pessimistic with assumptions different from the intermediate one: a new 25 per cent more infectious mutant spreads in August (it is not Delta plus, which is not more infectious than Delta variant).”

He also shared a graph that showed that the second wave is likely to plateau by mid-August and a possible third wave could reach its peak between October and November. In the pessimistic scenario, the third wave could witness daily Covid cases somewhere between 1,50,000 and 2,00,000 in India, Agrawal noted.

Comparing with second wave figures: This figure is less than half of what was recorded during the second wave which hit its peak in the first half of May. Hospitals were overburdened and the fatality rate reached a devastating peak at the time. On May 7, India had recorded 4,14,188 Covid-19 cases; this is the highest figure registered during the second wave.

In the case of a new mutant emerging, the third wave can spread rapidly but it will still be half of what the second wave was, Agrawal said. “Delta variant is infecting people who contracted a different variant earlier. So this has been taken into consideration,” he pointed out. As vaccination progresses, the possibility of a third or fourth wave reduce, he said.

In the optimistic scenario described by Agrawal, daily cases could be in the range of 50,000 to 1,00,000. In the intermediate scenario, the cases will be more than what is predicted for the optimistic scenario, the scientist said.

UK example: Another panel member, M Vidyasagar, predicted that hospitalisation could be less during the third wave. He gave the example of UK where in January over 60,000 cases were reported with daily deaths reaching 1,200. However, during the fourth wave, daily cases dropped to 21,000 and just 14 deaths per day. “Vaccination played a major role in bringing down the cases that needed hospitalisation in the UK. This has been factored in while coming out with the three scenarios,” Vidyasagar was quoted by PTI.

Delayed analysis: Finally, Agrawal also explained the reasons why the panel’s analysis for the third wave had been delayed.

“It took us a while to do the analysis for three reasons. First, loss of immunity in the recovered population. Second, vaccination induced immunity. Each of these two need to be estimated for the future.

“And third, how to incorporate these two factors in the Sutra model. Fortunately, it turned out that both can be incorporated by suitably changing contact rate and reach parameters… The first two factors required detailed analysis,” he tweeted.

Contact rate is how fast the infection spreads and reach parameter is described as the percentage of the population the pandemic is active in. Agrawal said that his team went through studies done in the past on loss of immunity while making these projections. “Similarly, we also looked at the projected vaccination rate over the next few months, including the effects of vaccine-hesitancy, and arrived at month-wise estimates for vaccination,” he said.