Second Covid wave in India saw significantly higher mortality across most age groups

India's second wave of COVID-19 was deadlier than the first, even as it struck a younger population. A study published in the Indian Journal of Medical Research found that mortality rose significantly across nearly every age group during the second surge—the exception being children under twenty. The difference was not merely statistical. More patients gasped for breath. More needed oxygen pumped into their lungs. More required machines to breathe for them. The virus, or the variants carrying it, or the sheer volume of cases overwhelming hospitals, had changed the shape of the crisis.

Researchers from the Indian Council of Medical Research, the All India Institute of Medical Sciences, and the National Centre for Disease Control analyzed data from a registry that had been tracking hospitalized COVID patients since September 2020. They compared two periods: the first wave, from September 1, 2020 through January 31, 2021, and the second wave, from February 1 through May 11, 2021. By the time the analysis was complete, nearly nineteen thousand patients had been enrolled—twelve thousand from the first wave, nearly seven thousand from the second. The data came from forty-one hospitals scattered across the country.

The second wave's patients were, on average, younger than those who had fallen ill during the first surge. A higher proportion came from the under-twenty and twenty-to-thirty-nine age brackets. Yet this demographic shift did not translate into milder illness. Fever remained the most common symptom in both waves. But in the second wave, something darker emerged: a significantly larger share of patients developed acute shortness of breath. More were diagnosed with acute respiratory distress syndrome. More required supplemental oxygen. More needed mechanical ventilation—machines that took over the work of breathing when the lungs could no longer manage alone. And across all age groups except the youngest, more died.

The study's authors noted the limitations of their work. The registry had not captured the very beginning of the first wave; data collection started in September 2020, missing the initial months of India's pandemic. The second wave's outcome data remained incomplete because hospitals were drowning in cases and had little time for paperwork. Some states, including Maharashtra and Kerala, contributed no data due to logistical obstacles. The picture, in other words, was incomplete. But it was the picture available, and it told a consistent story: the second wave was not simply a repeat of the first. It was, in some measurable way, worse.

India had experienced a period of relative calm between the two surges. Cases had declined through the fall and winter of 2020. Then, beginning in March 2021, the virus roared back. The second wave would prove to be the more severe of the two, at least by the metrics this study could measure. Why remained an open question—whether it was the virus itself, the variants spreading it, the exhaustion of the healthcare system, or some combination of these. But the data was clear: younger people were getting sick, and sicker people were dying.