Covid-19 is less deadlier than the other coronaviruses and if we find a vaccine that’s 70-80% efficacious, it will decrease the disease in the population by 50% or more, said microbiologist and vaccine scientist Dr Gagandeep Kang. She was in conversation with author and senior journalist Kaveree Bamzai in TNIE Expressions, a series of live webcasts with people who matter.
It’s been over six months since the Covid-19 pandemic hit the globe. What is it that we have learnt so far that can help us going forward?
One of the things we have learnt so far is this virus behaves in a predictable fashion. ...By and large, it is behaving like most RNA viruses which cause mucosal infection...This virus does not kill a lot of people that it infects — the numbers are scary because of how infectious this virus is. ...Not everybody infected is going to get severely ill or die. In fact, it’s a lot less deadlier than the other coronaviruses that we have dealt with, such as SARS and MERS. Here we are seeing mortality of less than 1%. What we should worry about is the unpredictability as to who will develop a severe disease. We have some clues such as age, co-morbidities, but some young people also badly get sick when 20 others of the same age around them get only asymptomatic infection. That’s because it’s not only about viruses but also hosts — some hosts react differently to the virus. There are signals but we don’t have a clear understanding of what actually happens in such cases.
When do you think a vaccine against Covid-19 can be available?
We will see the interim analysis of at least 3-4 vaccines under phase 3 trial sometime this year. We will know whether those results are going to work or not. If we are lucky and one or more vaccines have good results then it’s possible that a few doses might be available this year. But having enough of the vaccine and the distribution part may not be possible before mid-2021, if not later.
While some people want to be absolutely sure that the vaccines are safe and effective before being rolled out, there are political pressures, in India and other countries, to get the vaccines quickly. How can that be balanced?
One thing seems almost clear — it’s not going to be a perfect vaccine, certainly not the first-generation vaccine. That’s why the WHO, USFDA and now the Indian drug regulator have said that the vaccine needs to prevent disease in 50% of the people vaccinated. We may find a vaccine that’s 70-80% efficacious — it still has value because it will decrease the disease in the population by 50% or more. It means we are that much closer to herd immunity, so I don’t think we should wait for a perfect vaccine. But two things are very important—testing the vaccines on thousands of people and generating safety data from those people.
We have seen in some cases, like HIV, that even after research spanning decades, we don’t have a vaccine yet. Could that be a possibility in case of Covid-19?
In case of HIV, we could not have the vaccine because that affects immune cells, it destroys the immune system which is not what we are seeing in case of SARS CoV-2. It sets up autoimmunity but doesn’t go and infect the cells that make up the immune system.