The rapid spread of the second wave of COVID-19 in India means that it will be less protracted too with 40 per cent of India's population estimated to develop antibodies by the end of April.

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Research by Credit Suisse estimates that the faster the second wave rises, the faster it should fall. The analysis notes that the area under the curve matters, as the infection fatality rate is still 0.05 per cent against an all-cause mortality rate of 0.7 per cent. As much as 21 per cent of the population had antibodies by the end-December last year, while another 7 per cent are likely to be added by the end-April. Vaccination is likely to cover 12 per cent of the population by end-April, thus taking the percentage with antibodies to 40 which should bring down deaths, the analysis said.

A total of 87 per cent of deaths are in the 50-plus population; in this cohort, anti-body prevalence will be more than 50 per cent by the end of April, the report said. In addition to the 28 per cent population having antibodies via infections, an additional 13 per cent population would receive at least the first dose of the COVID vaccine by April end. The report noted that antibodies do work as 90 per cent of incremental cases in Mumbai came from high-rise buildings, which had only 16 per cent seroprevalence in the first wave, compared to 57 per cent in slums.

In Mumbai, while the number of cases are more evenly distributed among the adults, 87 per cent of deaths are among people aged 50 or above, in comparison to just 40 per cent of cases. This pattern has not changed in the second wave. As per the report, assuming that 15 million doses are administered to medical professionals, 24 per cent of the 45-plus age group are being vaccinated nationally. Assuming 55 million more doses by the end of April, 46 per cent of the 45-plus population would take at least one dose by the month-end.

Despite a much lower incremental case fatality rate (CFR), daily deaths are now close to the prior peak in September. The daily new cases are now 100 per cent above the September 2020 peak, while active cases are 46 per cent above the prior peak. The spike in active cases across most districts is causing panic and shortages, the report said. The incremental CFR in the second wave has been in the 0.5-0.6 per cent range, likely due to better testing. The infection-to-case ratio is likely at 15x now vs 28x earlier. The infection-fatality rate is 0.04-0.05 per cent while all-cause mortality is 0.7 per cent. Also, mobility indicators have shown some drop in April.