There was a time when India had been reporting close to 1,00,000 new Covid-19 cases each day and hospitals were overloaded with patients, but now the numbers have fallen drastically, to as low as 8,000 cases. However, the variant of the virus from South Africa is still a big concern and the pandemic has not come to its end by any means. Dr Satyajit Rath, immunologist and former professor at the National Institute of Immunology, and Dr Lalit Kant, former scientist and head of the Epidemiology and Communicable Diseases Division at ICMR, share their insights on the subject in an exclusive interview with The Daily Guardian. Excerpts:
Q: What can be the reason behind the declining number of Covid-19 cases in India? What is the mystery behind it?
Dr Satyajit Rath: Different countries have had different trajectories of the epidemic surging and receding; India’s is not particularly unique. I do not think that we reliably understand the reasons behind each specific pattern. That said, it is possible that the fastest rate of transmission in open-air countries such as India might be in heavily crowded urban working-class localities, and those may be saturated by now, leading to the currently relatively slow spread of the infection.
Dr Lalit Kant: There are many things which contribute to this. One thing is more people developing antibodies against the virus which gives them some kind of protection. I believe, in India, the proportion of cases is 20%- 80%, which means that severe cases are 20% and mild cases are 80%, in comparison to Western countries. In India, there are more cases of a milder infection or asymptomatic patients. The second reason (for the fall in cases) is that people in India spend more time outdoors, rather than indoors which has lesser air exchange. So, chances of the infection happening go down. There is also the composition of the age structure of the Indian population. Another reason can be the immunisation that we get here in the country, especially the BCG and measles vaccines. Wherever the BCG has been used, cases have been much less. So, there can be cross immunity, but all these things are still conjectured.
Q: What needs to be done if this virus mutates more? It is already happening in countries like South Africa and the UK.
Dr Satyajit Rath: All viruses mutate, especially RNA viruses like SARS-CoV-2 (or influenza, or HIV). They mutate everywhere, not simply in some countries. They do not actually mutate ‘more’ or ‘less; it is just that, since mutations happen in them along with growth, the more the growth of a virus, the more the mutations that accumulate. The greater the diversity of mutational changes in the virus population, the more the likelihood that some of those changes may be beneficial to the spread of the virus under prevailing conditions. That is likely why most of the virus variants that have emerged are better at spreading. As antibodies resulting from infection or vaccination become more and more common, variants that emerge will likely be resistant to such antibodies. At that point, new-generation vaccines will be needed. If we track the emergence of the mutations carefully, we will be in a good position to design such next-gen vaccines in good time.
Dr Lalit Kant: We had a system of testing people who are coming from other countries. A lot of countries have identified the South African strain. The South African strain appears to be more problematic as compared to the UK strain because some of the vaccines that underwent clinical trials against the South African strain found out that the efficacy levels dropped to just 55%. So, it’s important to monitor people who are coming from South Africa.
Q: Do you think we can face another viral pandemic in the future? What should be done to control such pandemics now?
Dr Satyajit Rath: Pandemics like this are natural phenomena. We have had them in the past, we will have them in the future. They are hard to predict specifically. We need to invest in tracking infectious diseases, in planning for vaccine manufacturing facilities for the public good, and in the careful provision of adequate public health facilities.
Dr Lalit Kant: Another pandemic will happen but we don’t know when it will happen and if it will be a respiratory infection. The government is stepping up towards controlling such pandemics with NIV labs, by increasing surveillance, investing in biotechnology and vaccines, etc. Each pandemic comes with its own challenges. So, we need to be prepared for such challenges.
