‘Only reasonable to expect surge in Kerala Covid cases after Onam’

Vinson Kurian Thiruvananthapuram | Updated on August 12, 2021

Rajeev Jayadevan

Wrong to obsess over the correlation, says Rajeev Jayadevan

A leading medical doctor, specialist, author and public educator has said that is only reasonable to expect a surge in Covid-19 cases a month or so after the Onam festival, just as was the case last year when both daily new cases and test positivity rate (TPR) peaked in Kerala.

“So, the TPR curve peaked in October last year, about a month after Onam,” Rajeev Jayadevan, who is a Scientific Adviser and past President of the Indian Medical Association, told BusinessLine. “That was expected because you don’t go to a peak just a day after the festivities.”

“People have to get symptoms and get tested, and the tested people have to be diagnosed, and the diagnosed people have to be reported; and the reported data have to be tallied, and the tallied data have to appear on the graph. So, it takes some time to come into public view.”


The peak may have occurred due to Onam, but it is important that we don’t give too much emphasis to the correlation. “Just because a cat crossed the road before one got a flat tyre doesn’t mean that the cat caused it. One may believe that the cat did, but that’s just a thought. Likewise, the peak might have occurred even without Onam last year. We don’t really know,” said Jayadevan.

“I think we need to be really honest in terms of the way we look at science. Here, we always look at the alternate hypothesis. It’s a hard fact that Kerala had a peak in October last year. There’s no doubt either that a year down the line, we have a fairly moderate degree of spread in the community.”

But cases are being also reported from South Karnataka and even Colombo in Sri Lanka. These areas have pretty much the same weather conditions, humidity, overcrowding and rain. The same goes for the North-Eastern States of India.

Weather, seasonal illnesses

Raised water vapour content in the air typically fuel seasonal afflictions. Viruses can spread more during this time and in these climes. So, there are multiple factors that contribute to the surge in the region. Even in the US, Louisiana and Florida are reporting a surge, and have similar climes.

May be there are factors beyond what we commonly acknowledge, said Jayadevan. And some people throw queries as to why the cases are high even in non-humid regions. It is more or less like asking one to choose between bikes or cars as the safer bet on roads. It’s difficult to provide an answer.

“We can’t control weather. The only variable under our control is how we behave during Onam. What we can do is to stop go seeing people and reduce social contact. At least during this Onam.”

Dissimilar Covid curves

On hindsight, one can see that Kerala’s curve has been entirely different from the national average. There was no similarity until the Delta variant struck like a tsunami. “If one takes the Delta variant aside, the Covid curve was so dissimilar that Kerala and India could have belonged to two planets.”

If one follows TPR graph in the same region, one can compare the value across spring versus winter. But one cannot compare the TPR of Kerala with that of Bihar or Assam or Meghalaya because those States may have a different strategy and Chhattisgarh yet another, said Jayadevan.

Breakthrough infections

The more the number of vaccinated people in a region, the more the number of breakthrough infections will be. This can easily be misinterpreted as if the vaccinated are triggering infections, which cannot be farther from truth. But breakthrough infections happen only with the vaccinated.

Jayadevan also sought dispel fears that Kerala’s high numbers could through up a new mutant.

A mutant may or may not emerge. These things happen and are part of continuous evolution. The Alpha variant had emerged in December last and replaced all others by March this year.

It was the dominant variant until March in India. And then came Delta which gained dominance in two months’ time. “After a few months from now, you may or may not find one. Just because a large number of people are getting infected in an area, one cannot jump to a conclusion.”

Anomalous response

Mutants have a timeline. They may appear ahead of time, but by the time they show up in terms of real statistics, it would be three or four months. There is no need to panic here, said Jayadevan.

On the one hand, Covid-19 has a part that mimics common cold, absolutely indistinguishable. It also has a virulent second part, which is tricky. “It is like a movie with a sequel. The second part is not the result of the virus but rather an anomalous response it elicits from mainly elderly hosts.”

Vaccines are very good at preventing part two (a severe disease), the scarier part. But they are not very good with the first (don’t prevent infections). This is a fact that public need to appreciate. But the problem is communicating with an audience that has very little idea of immunology.

“So, if you say it is the vaccinated people who are getting infected, then they come hammer and tongs at you, demonising the vaccine. Its very hard to communicate to them the fact hat vaccine is very good at preventing severe disease but not with preventing infection in the first place.”

Published on August 12, 2021

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