The results of the fourth nationwide serosurvey confirm the claim of a section of experts that a majority of Indians, in both urban and rural areas, have been exposed to the coronavirus. The survey conducted by the ICMR in June and early July, just after the second wave of the pandemic was abating, indicates that 68 per cent of Indians have Covid antibodies. This is a positive development at a time when the increasing caseload in Kerala, Maharashtra, Andhra Pradesh and pockets of the Northeast is stoking fears about a possible third wave of the pandemic. With more than 32 crore people having received at least one shot of the vaccine, there is a reasonable chance that 70 per cent Indians over the age of six have Covid antibodies. It would be hasty, however, to infer herd immunity dynamics from these figures and people must continue to remain vigilant. The ICMR has done the right thing by prefacing its survey with a note of caution against large congregations — one that is particularly salutary given that local-level heterogeneity in Covid exposure continues to provide the virus with suitable conditions to proliferate.
A situation in which a majority of people are asymptomatic carriers of an infection or display mild symptoms of a disease is usually reason for optimism during a confrontation against most viral pathogens. The latest serosurvey results could indicate why the Covid caseload has come down appreciably in most parts of the country in the past two months. But the depredations of the second wave should be enough of a caveat against reading signs of a larger immunity in the ICMR report. It shouldn’t be forgotten that in late January, a serosurvey in Delhi had found antibodies in more than 50 per cent of the city’s population. At that time, experts had counselled that mere presence of antibodies is no guarantee against contracting Covid — they had cited imponderables such as the quality of the antibodies and the virus’s ability to mutate. Their warnings rang true less than three months later, when the capital was amongst the worst hit by the second wave. The unfortunate turn of events in April and May should frame the context for reading the latest serosurvey results — no doubt reassuring, but no signal for dropping masks or jettisoning physical distancing norms.
Serosurveys and increasing vaccine coverage must also not lead to a slackening in testing drives, especially in parts of the country where the virus is still spreading. And in parts of the country where the virus is on the retreat, random testing can alert public health authorities to possible hotspots. At the same time, the government must continue to conduct serosurveys. Along with testing and genomic studies, such surveys are the surest ways of ascertaining the virus’s behaviour even when it might not appear lethal. They are invaluable sources of information, but not messengers of a return to normalcy.