No community transmission of Covid-19 a falsehood: noted epidemiologist

In a Q&A, Jayaprakash Muliyil, former Principal, Christian Medical College, explains why the lockdown was of little help in containing the virus

The Central government on Friday said that the national lockdown helped prevent 54,000 deaths and two million Covid-19 cases in India. In an interview with Somesh Jha, leading epidemiologist Jayaprakash Muliyil, former Principal, Christian Medical College, who is also a part of the research group assisting the National Task Force for Covid-19, discusses how the lockdown was of little help in containing the virus. He also talks about India already witnessing a community transmission and how herd immunity will be an inevitable consequence. Edited excerpts:

Do you think we adopted a reverse strategy – first we had the strictest of lockdown measures and now when cases are spiking we are easing the lockdown considerably?

You did the lockdown but how does the virus know there is lockdown? The virus is transmitting from one to another. When lockdown is implemented, human-to-human contact is reduced and transmission is low. But then you do a lockdown and say that one can buy vegetables for three hours. Let’s say you sit at home for 23 hours but for one hour you step out to buy essentials. You create a crowd and that is enough for transmission. On the one hand you call it a lockdown and on the other, you encourage crowding. Consequently, the lockdown created havoc but it didn’t stop people and did not stop the disease from spreading. In an ideal scenario, during a lockdown everybody should be locked in and should not move out, but it is not humanely possible. There will be riots. Then, we had the issue of the migrant workers who were trying to travel, which we didn’t anticipate. We locked people away from their homes and this caused more problems. Lockdown slowed down the transmission a bit in some parts of India but in most big cities, the transmission is happening quickly. Now if you say there is no community transmission that will be a falsehood.

When we last spoke over a month back, you had advocated building ‘herd immunity’ and now most political leaders have been talking about the need to live with the virus. Do you think we have gone in the direction of herd immunity?

In the beginning we all were anxious about the virus as it had just set in. The problem with this virus is that it’s not easy to get rid of. Kerala did exemplary work and managed to contain it but it’s not an easy task. In terms of controlling the viral diseases, Kerala’s efforts will always be described as a miraculous success. But they have a new problem now, as a huge number of Keralites will be returning home. But that’s a different issue. With the rest of India, the problem was that containment was not fast. This disease has one particular characteristic -- sub-clinical infection which is difficult to contain. For every case coming to the hospital, there are 80 other cases of sub-clinical infections. Now one of the aspects of the disease is that once the virus is there in the community it starts spreading easily. Why? Because today in India, we live in close contact with each other. As a consequence, the disease is spreading very easily. So a large part of population, though not immune, is susceptible. I wish we had a vaccine in place, but we don’t.

The question is do you think India is moving towards an unstated policy of herd immunity?

The concept of herd immunity comes in not as a plan but as an inevitable consequence. The point is people thought lockdown is the answer. Lockdown is a very hard measure as it destroys lives. As you can already see how much damage it has caused to family and livelihood, along with the inability to treat other diseases. There was thinking that in the short-term, maybe 3-4 weeks, we will be alright. But that’s also a long period as one cannot even travel to the next district. It becomes difficult for people. If you lock down completely, you can control Covid-19 but you will also destroy the economy and the people. Now coming to herd immunity, it is neither my invention nor can it be a strategy, but it’s a consequence of every viral epidemic, provided there are two conditions: transmission takes place from person to person and it causes life-long immunity. If the two characteristics are present then herd immunity is an automatic outcome. We know from the beginning that this particular disease was transmitted from one person to the other. That’s why we suggested physical distancing and mask. The argument in the beginning was will it produce lasting immunity? Some experts first thought there was no immunity at all. Then they found that yes, there is immunity but it isn't really protective. What is essentially required is a T-cell-mediated immunity. This has also been demonstrated. So this particular disease has satisfied the two important criteria, which includes the fact that most people will develop T-cell immunity, in simple words a lasting immunity.

Is herd immunity possible even without a vaccine?

The thing is that the virus doesn’t know how the person got immunity – is it through a person or a vaccine? Some people think only a vaccine can build herd immunity. Of course, it’s a better way to get herd immunity through a vaccine as you can contain deaths. But right now there is no vaccine and the disease is spreading. Disease also produces herd immunity. It will stop on its own without infecting everybody but will come back after sometime. For example, measles infected a large population but not everybody. This was before the vaccine came, herd immunity stepped in but the virus came back after three years because of the susceptible population (mostly the newly born). Herd immunity is not my invention. Viral diseases, even before a vaccine, cause some sort of herd immunity. I didn’t suggest it to be a strategy. All I said remember this will happen but it will stop after 60 per cent of the population is infected. Now, I may be wrong about 60 per cent or 65 per cent because this is the first time this disease has come but we had to make a guess from the R0 (R-naught). In cities like Mumbai, Delhi and Chennai herd immunity will set in quicker but the diseases may come back in 2-3 years and by that time we will have a vaccine. The fact that this virus produces good immunity is good news for us. You know why? Once you get infected or are found to be tested positive, you can happily look around and say I will never ever get Covid-19.

But is this proven? There are reports of people getting re-infected with the virus…

First, they said there is no protective IgT but we found it. Then they said there were no neutralising antibodies but we found that, too. As I told you before, the disease produces T-cell-mediated immunity which is life-long. The study which showed that some people were getting re-infected was wrong. CDC (Centers for Disease Control and Prevention in the United States) examined it and found that these were non-viable viral RNAs, which means that these people cannot infect others. So, re-infection was a false alarm. So, immunity from the virus is lasting.

Now because I told you immunity is good and it has got a long lasting immunity, it also means that a vaccine that comes out will also be good. The disease which produces good natural immunity helps you to produce good vaccine. The only issue is that the company which produces it has to show it does work well and is safe.