Based on the growth rate of cases, the pandemic can be divided into two broad phases — the early phase that started in January last year, peaked around September and was cooling off until mid-February this year and the latest phase that started after February in most states (except Maharashtra and Punjab) where infections are again rising. Of course, the rise may also be due to reduced curbs and increased laxity. Still, data suggest that in five states/UTs — Maharashtra, Punjab, Gujarat, Madhya Pradesh and Chandigarh — the second wave seems to be in full flow with average daily fresh cases surpassing those in the earlier phase.
Fatality rate indicates virus has mutated to be more infective, less lethal: Expert
In Maharashtra, the first wave started on March 9, 2020 and ended on December 22, 2020, when daily average of cases reached its minimum value. In this 288-day period, 19 lakh cases were reported, averaging 6,606 a day. Since December 22, the state is witnessing another surge in cases and the 99 days since then till March 31, 2021 have seen 9.1 lakh cases, an average of 9,197 cases a day.
Similarly, the daily average of cases in Punjab is 1,069 for this phase compared to 532 earlier. For Gujarat, Madhya Pradesh and Chandigarh, this average is 888, 828, and 128 respectively for this phase. In the same order, these states and UTs averaged 805, 780 and 64 in the earlier phase.
Apart from the increase in daily cases, another indicator consistent among all these states and UTs in the ongoing phase of the pandemic is a dramatic drop in the case fatality rate — deaths per 100 infections. The CFR has dropped by 75% for Maharshtra, 41% for Punjab, 83% for Gujarat, 72% for Madhya Pradesh and 65% for Chandigarh. “The virus seems to have mutated to be more infective and less lethal as the overall case fatality rate at all-India level is about one-third of its previous value,” said Dr Sumit Ray, head of critical care medicine in Delhi’s Holy Family Hospital.
He explained that viruses typically mutate to increase their spread and survival and this has earlier happened to many viruses like the influenza virus. “Viruses go out there to increase the survival of their species, and we are collateral damage,” he said.
He also added that the low fatality in the ongoing phase might also be because the virus is infecting more young patients (possibly because a fair number of elderly are vaccinated and also because the young are more mobile and hence more exposed). Further, a better understanding of the pathophysiology now than at the onset of Covid-19 means patients are being treated more appropriately. He cautioned that deaths lag by about 10 days from the surge in cases. “Still, the patterns so far show a significant decline,” he said.
The data shows that among 21 of these 23 states and UTs, cases have been steadily increasing for at least 30 days, Bihar and Odisha being the only exceptions.