NEW DELHI (BLOOMBERG) - The results of India's first nationwide serological survey suggests that more than six million people were infected with the coronavirus as early as May, which would place the country well ahead of the current official tally in the United States.
The survey enrolled 28,000 individuals across 70 districts in 21 of India's 29 states. The study was conducted from May 11 to June 4. The number of infections is an estimate, extrapolating the results of the study to encompass the entire population.
"The findings of the first national population-based sero-survey indicated that 0.73 per cent of adults in India were exposed to Sars-CoV-2 infection, amounting to 6.4 million infections in total by early May 2020," the Indian Council of Medical Research (ICMR) said in its survey note.
The findings in one of the only nationwide serological surveys that's been conducted confirm suspicions that infections are being vastly under-counted, especially in places where testing is inadequate like India and the US.
Experts also believe that the death toll from the coronavirus is far higher than the over 900,000 that have been reported.
"The low prevalence observed in most districts indicates that India is in early phase of the epidemic and the majority of the Indian population is still susceptible" to the virus, the survey found.
"It is, therefore, necessary to continue to implement the context-specific containment measures including the testing of all symptomatics, isolating positive cases and tracing high-risk contacts to slow transmission and to prevent the overburdening of the health system."
India imposed a strict nationwide lockdown at the end of March but was unable to flatten its virus curve. Its testing strategy also continued to be patchy. In some parts of the country, including capital Delhi, asymptomatic contacts of infected people were not being tested until June.
The national strategy, set out by the ICMR, also allowed only one-time testing for asymptomatic contacts. It was only last week that the country allowed testing on demand.
India's confirmed infections tally stands at nearly 4.6 million, behind only the US which has about 6.4 million confirmed cases, according to data from Johns Hopkins University.
The South Asian nation of 1.3 billion is now adding well over 85,000 new infections a day. Health experts say India's coronavirus outbreak is likely to surpass the US' as the world's biggest.
In mid-May, around when the ICMR survey began, India had reported a total of just over 85,000 confirmed infections.
One main reason for the huge variance is that the earlier testing strategy of the country was primarily focused on those who had travelled internationally or those who were symptomatic, said an official with first-hand information of the survey, who asked not to be identified, citing rules on speaking with the media.
Going forward, the cases are likely to increase, as is mortality, and an additional 100,000 cases every day will be a huge burden on the healthcare system, the official said, adding that hospital beds may be a serious worry going forward.
Official US coronavirus figures are also likely to be lower than the actual number of cases there. No similar national effort has been published, though a sero-survey conducted in New York, one of the early virus epicentres, showed that nearly 20 per cent of the population had virus antibodies.
Officials at the Health Ministry and ICMR did not immediately comment on the survey findings.