New Delhi: India could be missing 23 infections for every reported Covid-19 case in the country, according to estimates shared by NITI Aayog member (health) Dr V.K. Paul Thursday.
Rejecting mortality numbers published in The New York Times, Dr Paul said the government estimates that India has an infection fatality rate of 0.05%.
With the country having reported 3,15,235 deaths till Thursday morning, this would mean that the total infections in the country stand at 63,04,70,000, against a total figure of 2,73,69,093 cases. This means India is undercounting infection by a factor of 23.
In epidemiological terms, a case is an infection that has been detected using a test and is likely symptomatic. An infection is the presence of a virus in a person without the outward manifestations of the disease or a positive laboratory report.
“The (NYT) estimates have been done ad hoc and without any basis; there are two parts — quoted cases is what percentage of viral infections. Because this virus infects a large number of people only some people get symptoms. This is well-known. There is a universe where infection is not known — if it is to be ascertained, every day or every week the entire population needs to be tested…saying that the infection is 10-15 times of reported, it doesn’t bother,” Dr Paul said.
He added that the problem arises when a certain number is thrown as mortality. “As per our estimates, infection fatality is 0.05% and case fatality rate is 1.15%. When somebody attaches a number without thinking of understanding… they (NYT) are taking 0.3% IFR (infection fatality rate) which is six times of 0.05% and 0.6% is 12 times. On what basis? No basis at all,” Dr Paul said, adding that India’s death reporting is “systematic and robust”.
Infection fatality is usually lower
Infection fatality is the percentage of deaths out of the total number of people infected, while CFR refers to the mortality percentages from among reported cases. Normally, such assessments are done from sero surveys which estimate the extent of infection in a community by assessing the presence of antibodies.
However, India has not had one since January this year. Since the last sero survey, which was concluded on 8 January, the country has reported over 1.5 crore cases. The sero survey estimated that India is missing 26 infections for every reported case.
Dr Paul cited the example of New York when he said that while the reported cases in the US city stood at 2 lakh in May, a sero survey found that the total number is actually 17 lakh, to emphasise that in a pandemic of this nature, it is not possible for anybody to detect the full extent of infections in the country.
“To say infections were underestimated is okay as it only shows that possibly a larger universe was affected by the virus. We have to keep that in mind while planning strategy and future implications, herd immunity etc.. It guides scientific discourse. Our sero survey shows that if we extrapolate we were missing infections by a factor of 26 and the survey before that showed it was 14. There are no issues there,” he said.
He conceded that The New York Times had used India’s own sero survey data from January to arrive at the infection estimates though whether they still hold is not known. “It is in the mortality figures that there are flaws and assumptions. This should not have been published,” he said.