Underreporting of cases and mortality were more acute in India during the second wave of Covid-19 pandemic compared to the first wave, and close to 7 lakh people died during the current surge till May 15 compared to nearly 1.16 lakh deaths reported, according to a mathematical model proposed by a team of researchers from Union of Michigan and the Indian Statistical Institute.

First wave

Their modelling studies suggested that India would have underreported cases by nearly 26.73 times and deaths by 5.77 times during the latest surge which commenced in March. In comparison, the underreporting of cases and mortality during the first wave was estimated to be 11.11 times and 3.56 times. Bhramar Mukherjee, a biostatistician with the University of Michigan, was the corresponding author of the study, which was recently posted on the preprint server MedrXiv.

“As of May 15, India reported 24.7 million cases, but our estimated number of infections is at 492 million, implying nearly 36 per cent of the population has had a past or active infection,” said Mukherjee.

Similarly, they estimated that as many as 1.21 million peopled would have succumbed to the infection, while reported deaths till May 15 were nearly 2.7 lakh. While 1.58 lakh people died during the first wave, the deaths reported during the second wave were around 1.16 lakh.

Interestingly, this is not the only group that had projected this seemingly high Indian Covid mortality.

Murad Banaji, an India-born mathematician at Middlesex University London, had estimated that deaths from the pandemic in the country would be anywhere between 3 and 8 times more than what is officially reported. The researchers said they have no rigorous way to validate the extent of underreporting in India because there is no all-cause mortality data from the last three years.

“All-cause mortality data should be released nationwide from 2019, 2020, 2021 month by month so that we can compare. We have seen so many studies in the last few weeks comparing death certificates issued being manifolds higher than reported deaths and higher than last year at this time,” Mukherjee told BusinessLine.

“We may never know what happened in rural India where most deaths go medically unreported anyways,” she said.

‘Need to be cautious’

Tanmay Mitra, a physicist-turned-systems immunologist at the Helmholtz Centre for Infection Research in Braunschweig, Germany, who is not connected with this research, said: “During the first wave, we were really misguided by the ICMR results of the sero-survey studies in metro cities, and even some people started to talk about herd immunity in India afterwards. So, we need to be very cautious regarding these estimates.”