In an interview that clearly provides cheerful news about COVID-19 at a time when cases are increasing by around 57,000 a day, the Director of the Indian Institute of Public Health in Gandhinagar, professor Dileep Mavalankar, says that a global literature review that his Institute has recently conducted and which was published last week by the Quarterly Journal of Medicine in Oxford, UK, shows that up to 80-90% of people living in the same household as someone who is diagnosed with COVID-19 do not get infected with the disease.
In other words, only 10-20% of household contacts of a confirmed COVID-19 case become infected.
In a 40-minute interview to Karan Thapar for The Wire, Mavalankar was asked whether this means that COVID-19 is not as infectious a disease as we thought.
In reply he said whilst that is one explanation he inclines towards the belief that the results show that everyone is not automatically susceptible to the disease. As he put it: “We need to rethink about the susceptibility of individuals to this virus”.
As he put it, this means: “A lot of us are a lot safer than we thought we would be.”
Mavalankar told The Wire that his findings corroborate and seem to confirm the ‘immunological black matter’ theory propounded by Karl Friston, a neuro-scientist at University College London, who has argued that perhaps as many as 50% of any population do not become susceptible to a virus because of such factors as cross immunity and geographical isolation.
He said that his results, seen in the light of Karl Friston’s concept, have very important implications for herd immunity.
As he explained, if up to 50% of the population is not susceptible to a virus then even with 23-25% sero-positive levels herd immunity is achievable. To illustrate his point, Mavalankar said this is perhaps why COVID-19 is declining in Delhi even though the sero-positive level, established by a recent survey, is just 23%. Mavalankar also cited the central zone of Ahmedabad where the disease is declining after this area reached sero-positive levels of 28%.
In fact, Mavalankar said that he believes something similar lies behind the sharp decline in the disease in cities like New York and London. In each case the levels of sero-positivity when added to the theoretical assumption that 50% of the population is not susceptible to a virus take the area to herd immunity levels.
At one point in the interview Mavalankar said “Delhi lends credence to (Karl Friston’s) belief that 50% of the population are not susceptible to any virus”.
He said that as yet he has received no criticism of his study which was published by the Quarterly Journal of Medicine last week but he welcomes such criticism if it’s forthcoming.
In part two of the interview Mavalankar was sharply critical of India’s attitude to medical and epidemiological statistics. He said we need more careful analysis of statistics to see the full picture and thus devise the correct prevention measures. He said whilst we have nationwide statistics what we need is for them to be further broken down in terms of urban versus rural, male versus female and also by age groups.
He added the data also needs to be broken down regionally if not district-wise.
As things stand, Mavalankar said: “In India the epidemiologic data is like a jigsaw puzzle with various pieces being held with various agencies and no agency is putting all the pieces together to get the full picture.” He said this is because in India we have not developed and given importance to medical statistics and epidemiological statistics. We need to develop the right attitude to such bodies of work and only then will we be able to properly analyse what is potentially already known to us.
The above is a paraphrased precis of Dileep Mavalankar’s interview to Karan Thapar for The Wire. Please see the full interview for accurate details.
