Home >Opinion >Views >Our long-drawn quest for real herd immunity

The bulls of our stock markets may have achieved herd immunity from covid quite a while ago, thanks to global doses of cash injections by central banks, but the real thing—as in, the relative safety from viral infection afforded by most of whom we mingle with being immune—is still a long way ahead. So, while reports of India having crossed a significant threshold of sero-positivity, with two of every three Indians in a sample found to have covid antibodies, should cheer us up, it must not send us down a familiar slope of complacency. With the likelihood of a third wave around the bend anything but low, we can afford to get lulled into a fantasy of relief only to our grief. Serological surveys do not reveal much about our overall state of vulnerability, especially in contrast with actual vaccination coverage, which would mean a whole lot more, though even this need not quell a pandemic that we simply must—once and for all.

The relative irrelevance of blood-scan data doesn’t mean we shouldn’t be heartened. It was the fourth round of tests done to gauge the prevalence of covid antibodies among us, and it found 67.6% of Indians aged above six had proteins formed specifically to neutralize Sars-Cov-2, up from 24.1% in early 2021, as inferred from a survey conducted by the Indian Council of Medical Research (ICMR). Carried out in June and July, after our grisly second wave had begun to ebb, its sample of 28,975 included under-18s for the first time. Our rural-urban split of seropositivity was found to be nearly even, and over half those kids had virus-fighters. If the ICMR’s test selections were sufficiently random, with everyone almost equally likely to be picked, then the result can be taken to represent the country at large. For herd immunity to kick in, a condition must be met: enough people around should get virus-resistant before the covid-exposure risk of anyone who is not immune drops off. Statistical models had indicated two-thirds of a population as that mark. However, these constructs of theory have not yet been borne out by experience.

Covid’s pathology is such that detectable levels of antibodies need not deliver full resistance, though it may reduce the severity of illness. Variants of the virus abound. What marked India’s second wave out was its Delta proliferation, with this mutant likelier to escape an antibody attack on it than other versions, and the pathogen’s mutation path remains unknown. Vaccines offer greater confidence, as their dosage is calibrated finely to safeguard us. At last count, we had given 325 million Indians at least one dose, with 85 million fully vaccinated. Not only is this pace of progress too tardy for comfort, our jabs don’t perform as well against Delta as we’d hoped. These complications led some experts to revise their projection of herd-safety to 80%, though such calculations have so many caveats that they often amount to educated guesswork. Accuracy, however, isn’t as vital as prudence at this juncture. We have lost over 400,000 lives to covid, an official count that may be less than a tenth of the actual toll, if an estimate by the US-based Center for Global Development (echoing other global reports) is taken at face value. Covid has excoriated lives, livelihoods and life-savings. One study said households had spent over 64,000 crore on tests and hospital bills between last April and this June. Our health crisis is not over, sadly, and the ICMR study provides no reason at all to relax. Let’s not be foolhardy.

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