Vaccination coupled with Covid-appropriate behaviour is the way forward, even as the pandemic wanes and the disease becomes endemic, says Dr Randeep Guleria, director of the All India Institute of Medical Sciences, in a free-wheeling interview with Prerna Katiyar. Edited excerpts:
The Subject Expert Committee on Covid-19 has recommended vaccination for children. What is the feasibility given that the two vaccines likely to be approved for kids are Covaxin with a pretty low production level, and that Zydus has not started production yet?
The thing to remember in vaccinating children is that healthy children usually have mild disease. Therefore, if we roll it out, we must focus on children with comorbidities as they have a higher chance of dying and having severe illness with hospitalisation. That strategy of prioritisation is being developed just as we did in case of adults. The basic aim of vaccination, even in children, is to avoid severe illness and deaths. Once that is achieved, the next aim will be to decrease cases of mild illness by vaccinating as many people as we can. For children too, it will start with a high-risk group.
FDA has approved booster shots of Moderna and J&J. Are there plans to approve the same and do you think it is necessary?
Currently, I don’t think there is a need for a booster shot. If you look at data emerging from outside where there is still a surge in the number of cases, you find that if the people are vaccinated even with the initial dose, the area is not seeing a surge in hospitalisation or large breakthrough infection. This suggests that the vaccine is holding out and is still effective in preventing severe disease or deaths. So the priority should be to vaccinate as many people as we can with the first doses rather than giving additional doses to people, especially when we do not know how much it will benefit unless we find a high number of breakthrough cases in the elderly or a particular group which currently we are not. Also, this will deprive others as vaccine doses are limited. So we may need a booster dose in the future, but data suggest it is not required right now. Secondly, when we talk about booster dose, timing is important. It can’t be based on antibodies. So, should it be given after nine months or one year of the last dose? That data has to come out in a clear manner. Then should it be a repeat of the initial vaccine? What is the advantage of mix and match as some data show this can give better immune response? What combination should be there? Then what should be the priority group? Once all this is decided, only then can we move forward. Currently, we can’t say straight away that we need a booster dose.
As the vaccination rates rise, do we need to start looking at more metrics than just number of cases in order to make decisions on public health and reasonable precautions?
Yes definitely. We are now looking at different scenarios at some places where we are not seeing a large number of cases. So the number of cases can no longer be the defining factor. Defining factor could be the change in the number of cases or number of hospitalisations over a period of time like a week. Your baseline can’t be an absolute number but a trend. If one sees a trend of increasing cases, one can argue that the trend is on the upside which should alert people about the changing profile of the area. Then you should look at more aggressive testing surveillance and even genome sequencing to see if this is the same strain or a new strain is evolving.
How should people and the government look at Covid risks in a more and more vaccinated country?
There are two issues here: one, vaccination is a good protection but with immunity waning over time, it has its own limitations. Secondly, with new strains, the efficacy of the vaccine will come down because now the virus is multiplying in a vaccinated population. Previously the virus was not multiplying in a population that was vaccinated. So you were not seeing that much mutation. The number of mutations we have seen this year is much more than last year in terms of variants of concern. Also, no matter what the variant, Covid appropriate behaviour will still protect us. The chain of transmission can still be stopped this way. Vaccination is not a substitute for a Covid-appropriate behaviour but it is complement to it.
Do you think it is necessary to develop new versions of existing vaccines after taking inactivated viruses of new Covid variants?
Yes, this will happen and is happening. Lot of vaccine manufacturers are already in research. We could have next-gen vaccines which cover for the delta or beta variants. Also we could be looking at a bivalent or trivalent vaccine. Current vaccines have one strain but suppose we have a bivalent one that protects you both against delta and another variant-which is more effective. So in the near future, we may have next-generation vaccines which may cover for the new variants and may be bivalent or trivalent.
Latest serological survey shows 90% of people in Delhi have antibodies. So how would endemic be defined in case of Covid19 going forward?
Two things are important. A pandemic becomes endemic if you continue to have a few cases but it does not cause significant surge the way we saw in the first and second waves. Also, there is a good amount of immunity in the population so that the number of cases is limited. But the important thing is we will gradually reach that stage. Currently, it’s difficult to say we have reached that stage because right now we have immunity against a particular variant. This will wane with time. We are looking at antibodies present against a particular variant that may be circulating at that particular time. If you get a new variant, the efficacy of the antibodies will wane. So when we talk of good or herd immunity it is against a particular strain of the virus. If the virus changes and you get a new strain then the immunity against that strain will come down significantly and that is why we are more careful as we know the virus is still evolving – there is Delta plus variant, AY.4.2. So we need to see how it evolves but some degree of cross protection is always there. We have a good amount of immunity but a lot depends on how the virus evolves.