As India gears up for vaccination, where is the coronavirus headed?

It remains to be seen what effect the declining trend of virus will have on the vaccines and their trials.
Even as India readies for the mass immunisation drive, there has been a steady decline in the daily number of cases and deaths, since the peak of mid-September. Less than 300 daily coronavirus deaths were recorded in the country for the last 16 days with the national recovery rate improving to 96.42 per cent, according to data from the union health ministry. Given that we will never know the true numbers during the pandemic or even after it, the trajectory is important and it has been on the downward slope, which leads to some pressing questions - Is the worst of the pandemic over? Are the numbers for real or there are other reasons like less testing or non-reporting of cases? Can we say that we are safe now? Will the virus pick up pace and spread again in the future, etc.

It is hard to say if the first wave is ending and if there would be a second one. That depends on the number of people who have been exposed to the virus. Considering that India went through two important periods without any significant upturn – Dussehra to Diwali festive season and elections that followed, experts say it is safe to assume that the epidemic is under control. And India is relatively well placed as a percentage of population and in terms of the mortality rates. It currently stands at 1.44 per cent. The anticipated horror based on western modelling turned out a to be a little off the mark.

Even with a mutant, the country is not seeing the sudden spike in cases, and that is likely because, unlike early last year, authorities have not been caught off guard. People are more aware now, and public health measures were already in place when the variant entered, even though it is highly likely that we are under-reporting the new mutant cases.

The second Indian Council of Medical Research (ICMR) sero-survey showed an average 6.6 per cent positivity across 70 districts. This translates to 90 to 100 million people. Data from Thyrocare puts the number much higher – 300 to 400 million.

"Outbreak modelling for India suggests about 30 per cent overall infection, with 50 per cent in large and densely populated cities. I think there would be enough infected people and we will not see another peak", said Shahid Jameel, a noted virologist, and the director of the Trivedi School of Biosciences at Ashoka University, adding that nothing has changed drastically in testing or behaviours since the peak. "So relatively speaking, it’s a downward trajectory. But the country average hides many localised spikes and that would continue".

"What we are seeing is a complex mixture of high exposure in densely populated areas (cities) where the outbreak also moves faster, and low exposure in villages and rural districts where the outbreak may still be expanding, but doing so slowly. This will create a situation where the return to baseline will be prolonged", he said.

"This is completely anticipated and the expected trend of decline. The worst of the epidemic is much much behind us" but it has also come with a bonus and that is the mortality rates are way lower compared to the rest of the world," said Dr Jayaprakash Muliyil, the former principal of Christian Medical College (CMC) and one of India's highly regarded epidemiologists.

The true nature of the outbreak is always difficult to gauge, but nation-wide hiding of a large number of cases and deaths is very difficult. One can also claim the nation-wide mortality is low because dead bodies are being hidden, but how many thousands of deaths can you hide is the question. That's very difficult to do.

"We've either reached or approaching the herd-immunity levels in many parts of the country. This is happening at localised levels, but when sufficient areas reach there, it becomes a larger chunk. Experience in some areas like Dharavi suggests, it reached there first. In that locality, the virus stopped transmitting because it hardly can pass from one person to another. In contrast, Kerala will take a little longer to get to that stage. In Tamil Nadu, more than half the districts are reporting cases in single digits even when there are large number of people still yet to get infected and vulnerable. That's due to the density of those immune or infected are high and the transmission dynamics have slowed down," Dr Muliyil told Business Standard.

"We may be closer in some, but not all locations," said Dr Jameel.

K Srinath Reddy, the president of the Public Health Foundation of India (PHFI), who also serves as the adjunct professor of Epidemiology at Harvard, says, unless, you have a nation-wide antibody survey, you cannot say what the level of virus exposure is and determine the herd immunity levels. It may be the case at local levels. But we have to note that herd immunity is for the population and not for the person. For instance, if a person steps out and moves to another area, where there is not enough protection, he is likely to get infected.

The science behind what experts say is, the moment the intensity of the immunity increases, in terms of proportion of the population, new case formations come down. Even if it varies depending on transmissibility of virus and the function of density of population, most epidemiologists believe 60 per cent or above population needs to get infected to reach the herd immunity in local areas or at a pan-India level.

Does it mean we all are safe now? "Absolutely not" says Dr. Muliyil. There are still new cases emerging, and with new festivals looming in parts of southern India, for instance, the Tamil and Telugu New Years and the harvest festivals, that is Pongal, one should still be worried.

"A large number of educated, well to do people, have been carefully avoiding the disease by taking all the precautions, by masking themselves, staying at home among many other things. And the question is how long will they be able to do that. Supposing they sneak out in the next few months and the bubbles break. We may get fresh outbreaks, and this has happened in Delhi. So we can say that we are not fully immune, because some people are guarding themselves. I think we will need to vaccinate the elite much sooner. For the ordinary class, they have enough amount of immunity, as they had no choice but to face the virus," he says.

"We can never say that we are safe till we are sure that we aren't seeing any upsurge of cases in any part of the country over a period. With the new mutations detected in the country, we should be careful and wait and see if that leads to any upsurge. We have to continue our public health monitoring to see that there is no second surge. We cannot completely close the book on the pandemic, all we can say is it is well contained, and under control," prof Reddy told Business Standard.

On the vaccination front, experts say the government hit the right note as far as prioritisation of people is concerned, even as they questioned the rushed approval. They say inoculation should be done judiciously, because we still don't know how good the vaccine (Bharat Biotech's Covaxin) is.

"Phase-3 trial is suppose to tell you how effective the vaccine is. Vaccine can produce antibodies, but that doesn't mean it prevents the disease. If you can't prevent the death or disease, why the hell are we buying vaccine and that's precisely why we have to prove it first. The minimum thing you should do before you give it to people is to demonstrate that it actually works. Am little concerned that why we are in a hurry, because at the moment things are quietening down," said Dr Muliyil.

"Am not questioning the vaccines, am questioning the way in which the permissions were given. While we talk about the need for vaccines, we need to create confidence in the people and the way to do it is be open about what's being done, that is if there is evidence to prove efficacy and the lacunae, if there is any," said Professor Reddy.

It remains to be seen what effect the declining trend of virus will have on the vaccines and their trials. As the epidemic comes down, with multiple indegenously developed vaccines still in clinical trial stages, it may become more and more difficult to find volunteers for testing.

Dr Jameel feels vaccination shouldn't depend upon the speculation of how many infections we have as it's difficult to know on an individual basis who was exposed and if so, do they have protective immunity.

"Testing before giving a vaccine may not be good, as it would double cost and logistics. It’s easier to vaccinate everyone at risk, who is willing to be vaccinated. Further, with a more contagious (though not more lethal) variant now in India, we don’t yet know how the transmission will play out. Now that vaccines are becoming available, they should be given to everyone," he says.

With the inoculation set to begin on January 16 and the virus trajectory already on the decline, where will India be placed two to three months down the line: "If you're a goal keeper, it doesn't matter if the ball comes from the left or right, you should be ready and try your best to field it. Likewise, whether it is the original virus or mutant virus, first peak or second peak, vaccine or no vaccine, people should take enough precautions to guard themselves," says Professor Reddy.

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