A study of the COVID fatality rates in India during waves 1 and 2

By Angela Betsaida B. Laguipo, BSNJun 3 2021

One of the most affected countries during the coronavirus disease (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is India. To date, the country reports over 28 million cases and more than 335,000 deaths. However, the underreporting and deaths associated with COVID-19 in India have been a subject of debate.

A team of researchers at the Department of Biostatistics, University of Michigan estimated the underreporting factor for infections using publicly available data released by the Indian Council of Medical Research on the reported number of cases and national seroprevalence surveys.

The study, which appeared on the pre-print server medRxiv*, reports that when pandemic waves 1 and 2 are combined as of May 15, the estimated combined fatality rate is 0.25 percent.

In August 2020, India was predicted to surpass the United States in terms of reported cases of COVID-19. However, the country reported a steady decline for nearly five months, but a second pandemic wave occurred, causing skyrocketing cases.

The highest number of daily new cases in the second wave was reported on May 6, 2021, reaching a staggering 414,280.

Study: Estimating the wave 1 and wave 2 infection fatality rates from SARS-CoV-2 in India. Image Credit: Exposure Visuals / Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Infection fatality rate (IFR)

The infection fatality rate (IFR) represents the proportion of deaths among all infected individuals, including all asymptomatic and undiagnosed ones. It differs from case fatality rate (CFR) because it estimates the fatality rate in both sick and healthy infected cases. This applies to the COVID-19 pandemic since many patients infected with SARS-CoV-2 do not develop any symptoms.

In the current report, the team estimated the infection fatality rate (OFR) inferred from seroprevalence studies. To arrive at the study findings, the team used a compartmental epidemiologic model to estimate the undetected number of infections and deaths, acquiring estimates of the possible underreporting factors.

From there, the team compared the serosurvey-based estimates of IFR with the model-based estimate. The team also carried the study in two periods, including the first wave between April 1, 2020, and January 31, 2021, and the second wave that occurred between February 1, 2021, and May 15, 2021.

The results showed that during wave 1, the observed case fatality rate in India is low. With over 154,000 deaths and 10.76 million cases as of January 31, 2021, the estimated CFR is 1.435 percent. The estimated number of infections from the January seroprevalence survey showed an approximate infection fatality rate of 0.09 percent.

Observed and estimated case (A) and death (B) counts associated with SARS-CoV-2 in India for waves 1 and 2.

For the second wave, underreporting factors for infections increase to 26.77 and 5.77 for deaths. Relying only on the reported deaths, the estimated IFR is 0.13 percent. Combined, the two waves incurred an estimated number of infections and deaths with an infection fatality rate of 0.25 percent.

In a nutshell, the team noted that despite accounting for underreported deaths, the large number of asymptomatic or undetected infections showed a lower IFR in India compared with other Western countries.

A lower IFR in the second pandemic wave in India could be due to two reasons. One is that they do not have the same length of the follow-up period. Another reason could be due to the different age composition of the infected population in the two waves. In the second wave, younger populations were reported to be infected more often. Also, they are at a lower cost of COVID-19 mortality.

“A fraction of the older population (aged 65+ years) also got vaccinated during wave 2,” the researchers noted in the study.

“However, this hypothesis about reduced fatality rates in wave 2 cannot be verified without more granular, age-sex stratified nationwide time-series data on case and death counts, which is currently unavailable,” they added.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources