India may have over 70 crore people infected with Covid-19 in the current second wave — much higher than the official figure of over 2 crore, comprising both the waves.
A report by The New York Times drew up estimates suggesting that India's second wave of the pandemic is much larger than what the official accounts suggest.
The estimates suggest three different scenarios of India's current Covid-19 wave — a 'conservative scenario', a 'more likely scenario' and a 'worse scenario'.
Under the 'worse case scenario', the NYT estimates that more than 70 crore people may have contracted Covid, while the actual death toll stood at 40 lakh — higher than India's official toll of over 3 lakh.
"This scenario uses a slightly higher estimate of true infections per known case, to account for the current wave. The infection fatality rate is also higher — double the rate of the previous scenario, at 0.6 percent — to take into account the tremendous stress that India's health system has been under during the current wave," the NYT report said.
The NYT estimates were based on an analysis of the cases and deaths and also on the three national sero surveys conducted last year during the first wave. The surveys were done to check the presence of Covid antibodies in people.
"All three have found that the true number of infections drastically exceeded the number of confirmed cases at the time in question," it said.
The report said that the results of each survey showed an infection prevalence between 13.5 and 28.5 times higher than the official figure at those points during the pandemic.
"The severity of underreporting may have increased or decreased since the last serosurvey was completed, but if it has held steady, that would suggest that almost half of India's population may have had the virus," the report added.
NYT further said getting a "clear picture of the total number of infections in India is hard because of poor record-keeping and a lack of widespread testing".
NYT quoted Kayoko Shioda, an epidemiologist at Emory University, as saying that "even the large multipliers found in the serosurveys may rely on undercounts of the true number of infections".
The reason, she said, is that the "concentration of antibodies drops in the months after an infection, making them harder to detect".
She added that the actual number would be much higher if the surveys were able to detect everyone who has contracted the infection.