ICMR’s serological survey findings may have relevance for modifying vaccination policy
The results of the ICMR’s third serological survey to ascertain the spread of COVID-19 show that nearly one in five Indians — about 270 million — may have been infected. The headline findings were publicised at a press conference and it will be a while before granular details of the course of the infection — as was known till December — will be made public in a peer-reviewed journal. However, what is known so far is that compared to August — when data for the second serological survey was announced — there has been a three-fold rise in infections. There has also been a five-fold rise (in percentage terms) of the infection in those aged 10-17 years. The third edition also included a serological survey of doctors, nurses and paramedical staff, revealing that nearly 25% — significantly above the national average — had been infected. Compared to reports of city-focused serology surveys in Delhi and mathematical modelling estimates, the ICMR survey-results appear to be more conservative in estimating the true spread. Experts of various hues point to the declining trend in infections since September, and the absence of multiple peaks in coronavirus cases as a pointer to the spread being far wider and speeding up ‘herd immunity’— a state when a significant proportion of people in a locale have been infected, thereby retarding future spread. But it would be wrong to derive comfort from this situation. The ICMR emphasises that the results point to a significant number still potentially vulnerable, underscoring the need to be vaccinated and continuing with distancing and masking up. Also, neither this survey nor any city-wide survey has evaluated how long antibodies persist and if certain virus mutant variants can overcome the protection from antibodies.
Given that vaccines are round the corner for the general public and that no district has been immune from the virus, it is now no longer useful to know that 80% of India is still vulnerable. Rather, such surveys must shift focus to asking more granular questions: should the rise in spread among teenagers and children mean that they be considered for vaccination earlier than scheduled? Should companies accelerate trials to test protection in children? Should the rise in rural India — the survey is designed in a way to sample more villages than urban pockets — mean that they be given vaccines earlier? These and many more questions are no doubt already on the minds of specialist researchers but alongside the vaccination drives, the ICMR and the government health facilities must coordinate with a broader spectrum of specialists to investigate questions that can be used to guide and modify vaccination policy.