One of India’s highly regarded clinical scientists has said whilst it’s very unlikely someone who has recovered from COVID-19 will get a second infection after 4-5 months, as yet we have no idea whether that can happen after a year. Professor Gagandeep Kang of The Wellcome Trust Research Laboratory at the Christian Medical College in Vellore said: “The likelihood of someone getting a second infection after 4 months is not huge at all but after a year we don’t know as yet.”
Professor Kang, who won the Infosys Prize in 2016 and is the first Indian woman to be elected a fellow of Britain’s Royal Society in its 360 year history, also warned against making projections of how many COVID-19 cases India could have in the next one month and two months or attempt to predict when the country will reach its peak. She said projections need to take onboard the impact of the different mitigation efforts that have been made and you need sophisticated models to do this. She is working on such a model but it will be at least a couple of weeks before its ready and able to make reliable projections.
She said it’s hard to put a date or timeframe on when the country as a whole will reach its peak. This is because the disease is best seen in terms of the different locations, cities, regions where it’s happening and each of those has its own epidemic curve and each curve behaves differently depending upon the circumstances, the age profile, the mitigating factors, etc.
In a 50-minute interview to Karan Thapar for The Wire, Kang said the 3 million total cases India has crossed today and the rate of increase, which is just short of 70,000 per day, is “completely expected”. Given India’s population of 1.38 billion “this is what the trajectory will be”. More importantly, she added “We should expect this to continue for a while”.
Speaking about Delhi, Kang said: “Delhi has reached its peak for the first wave”. Whilst agreeing that “antigen tests are misleading” and, therefore, “the extent of deceleration in Delhi is questionable because it’s based on antigen testing”, she said she was reassured by other facts that Delhi looks like a good news story. The other facts she mentioned are hospitals, where the number of patients has fallen and they are no longer as full as they were, and the positivity rate, which has steadily gone down. On the 1st of July the positivity rate was 12.2%. It’s now around 7.1%.
However, Kang made a point of mentioning that antigen negative tests need to be followed up by a RT-PCR tests but this “is not being done”. Therefore, we are not making the requisite efforts to find out how much infection the antigen negative results are missing. As the ICMR itself accepts in its June 14 advisory, perhaps as many as 50% of antigen negative results could be incorrect.
Speaking about India’s mortality rate, which is 40 per million as of August 22, Kang said whilst it’s possible it’s under-reported she did not accept its under-reported by a factor of 5.29 as an article in The Hindu by Hemant Shewade and Giridara Gopal Parameswaran suggested. However, she did accept that the quantum of under-reporting “could increase” as the incidence of the disease shifts from metropolises like Delhi, Mumbai and Chennai to tier 2 and tier 3 towns and then, further, into rural India.
Kang also pointed out that the present day single-minded focus on COVID-19 means other chronic diseases like diabetes, TB and cardiovascular ailments but also maternal mortality are not getting the attention they deserve and deaths as a result of these is likely to go up.
Finally, Kang said there are several reasons, which are actually hypotheses, why India’s mortality rate (even if you believe its under-reported and multiply it by 2 or 3) is significantly lower than mortality rates in Europe and America. One reason/hypothesis is the age profile of the Indian population. 90% are under 60 and 83% under 50. The median age is 28-29. In Europe it’s in the mid or late 40s.
A second reason/hypothesis is that Indians have been subjected to more viruses and infections than people in Europe and America and, therefore, have acquired innate immunity. A third reason/hypotheses she mentioned is genetic. The virus reacts differently to different blood groups.
However, she pointed out India is not unique. All our neighbouring countries as well as others further afield, like the Philippines, Thailand and Indonesia, and practically all of sub-Saharan Africa (with the possible exception of South Africa) have similarly low mortality rates.
In part two of the interview (i.e. after the commercial break) the professor spoke to The Wire about herd immunity and Dr. Karl Friston’s theory of immunological dark matter. She also spoke about how long any immunity conferred by a Coronavirus infection will last.
Kang said the percentage of infection necessary for herd immunity to kick-in “depends on how you define the population and their intermingling with each other”. That’s why, she said, herd immunity is projected at levels that can vary considerably. It all depends upon what assumptions are being made. One critical factor which we understand very little about is how should we handle super-spreaders. What are the determinants of a super-spreading event, she asked. We just don’t know. Yet this is a critical element in determining herd immunity. Consequently, professor Kang did not specify at what percentage level of infection herd immunity would kick-in in India.
Speaking about Dr. Friston’s theory of immunological dark matter, Kang made it clear that she is not impressed by it and certainly not convinced by it. When asked if she was saying this theory “makes a virtue out of ignorance” she said that is precisely what she was saying.
Finally, in response to a question about how long the immunity conferred by an infection will last, Kang said this is something we are finding out about every day. COVID-19 is a new disease and there’s a lot we don’t know about it. One of the “don’t knows” is how long the immunity from infection will last. In response to a question, she said it’s possible that this could also have implications for the efficacy of a vaccine. It may only be effective for a limited period and, like the flu jab in Europe, it might be necessary to have it every year.
The above is a paraphrased precis of Gagandeep Kang’s interview to Karan Thapar for The Wire. Please see the full interview for accurate details.
