Express News Service
BENGALURU: While the country continues to reel under the second wave and deals with questions on the timing of vaccine doses and the need to ramp up vaccination strategies, Dr Gagandeep Kang, one of India’s best virologists and microbiologists with the Christian Medical College, Vellore, speaks to TNSE on some of the important aspects of mix and match of vaccines, the third wave and preparedness for it and most importantly, on data integration.
Just when we are seeing the second wave tapering, we are witnessing an increase in cases in Maharashtra and there is already talk about a third wave. When do you think we will see the third wave?The rapid decline of the second wave was due to the measures taken to suppress transmission of the virus like Covid curfews, restricting travel between districts and states, etc. But as soon as these are lifted and people start to move around, you are going to see a surge in cases. What we need to track now is not only the test positivity rates but also hospitalisations and mortality. They are the indicators of a coming wave. We also need to have strategies like what Maharashtra has developed. That is, to decide that if we reach a point, then we will introduce restrictions, and withdraw later.
There are confusing signals about the dosing gap for Covishield. The Lancet publication indicates that two doses with a shorter interval provides better efficacy. However, the Oxford vaccine group, in their preprint publications, says that a 10-month interval is fine for immunogenicity. And India has chosen a gap of 84 days. What is your advice to the government regarding the ideal interval for two doses of Covishield?There’s a difference between an ideal and practical scenario. The ideal interval between two doses is likely to be 4 to 6 months for most vaccinations. But, the one thing to remember is you need a minimum of a three-week gap; there is no maximum. The further out you push the second dose the greater likelihood of ultimate advantage. The question is how quickly do you want this advantage. If there is a situation where you need two doses to get complete or full protection, then you might want to bring it together closer. The question is what is likely to happen between the first and second dose towards exposure likelihood. If the exposure is low, then there is no issue with pushing the second dose far off. If exposure is high, then you need to strike a balance between exposure and immune response.
A study in the UK has found that alternating doses of vaccines generate robust immune responses against the SARS-CoV2 spike IgG protein. Do you recommend this mix-and-match? Is there any study being done in India in this regard?I absolutely think we should be doing these kinds of studies because we have products in India that are not available in other parts of the world. And, if they are going to be exported, as is the intention, they should do those studies so that we have information to offer about the advantages to the rest of the world, if there are any.
Which are the vaccines which can be studied in India?Sputnik has already had a mix-and-match study with one dose of Astrazeneca and one dose of Sputnik. We have to think of different permutations and evaluate all of them. It doesn’t need to be in large numbers as we are not looking for efficacy, we are looking for an immune response and measuring an antibody response or a T-cell response.We don’t know how it translates to efficacy, but there will surely be an advantage to having a better immune response.
You have been appointed as an adviser to the Karnataka Government for setting up a vaccination protocol and guide the vaccination drive. What are some of the strategies have you suggested?I have had several meetings and suggested some strategies which the government has said is proving to help. It’s some basic principles like identifying the high risk population – those who are having severe disease or people who are at the highest risk of transmission. We need to make sure we prioritise these groups. When you have a limited number of doses, you maximise the value of those doses by having a strategy. It should not be that to just distribute it widely across the state, but instead try to focus efforts so that you get the maximum time for the public.
Do you see a need to integrate data to catch the variants fast? Data is now everywhere: For instance, INSACOG, Aarogya Setu, Co-Win, eVin, manual data entries from NDHM, NCDIR, etc.This has been endlessly suggested to the government. It is important to understand that when people build data systems for a particular purpose, and if you want to use it for something else, then it must be possible for the data to talk to each other, to be integrated. Now, in public health terms, when a virus appears, you know there is an effort to make a vaccine or a drug you need clinical information, geographical info etc.
It just makes sense when you build a database right at the beginning so that we can do this. Unfortunately, that did not happen. We administered over 330 million doses of vaccine in this country and we don’t have any idea of how well or badly the vaccines are working. There’s one published paper from CMC Vellore that relies on the 10k healthcare workers. We had similar data reported from other places, but not yet published. But 10k out of 330 million doses? I think we are wasting information that would be good for us and good for the world.
Is it difficult to do this?This is not rocket science. Israel turned into a living laboratory. Israel has a very limited number of people and they were able to publish the data one month after they started vaccination. We are five-and-half months into it and we haven’t been able to put our data out there despite the fact that we have used ‘n’ times the vaccines Israel did.
To sum up, what are some of the things to do to beat the third wave?Other than Covid protocols, it is also important that we need to not only ramp up vaccination, but also prepare for ramping up our clinical capacity to handle cases when they occur. We are going to see long Covid and I think we need to be better prepared for both the treatment of people and also research on them so that we can develop better modes of treatment.
In terms of surveillance, our biggest risk are the variants. As long as replication occurs at a high rate, variants will continue to emerge. Our best chance of controlling them is to be able to identify them as a problem very early. The sooner we are going to get almost real-time whole genome sequencing of the virus the better for us.
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