Has India ushered in the third wave of Covid-19? According to a top city researcher, who has analysed the metrics of infection and death rate for over 15 months based on data uploaded daily, the third wave appears to have set in on July 4 to be precise.
Dr Vipin Srivastava, an eminent physicist and former pro-vice-chancellor, University of Hyderabad (UoH), told TOI that the pattern of new Covid-19 infections and deaths in the country since July 4 appeared similar to that of the first week of February 2021, when the second wave of Covid-19 hit the country peaking by April end. He cautioned that the third wave could pick up momentum if people failed to follow the Covid-19 protocol like social distancing, sanitisation, wearing of masks, and vaccination. Dr Srivastava prepared graphs taking daily updates on Covid-19 by TOI for the last 461 days to unravel the wave pattern.
The physicist has developed three metrics on the progression of the pandemic after analysing the Covid-19 data on deaths for 461 days now. One of the metrics or measures analysed, shows the signs of onset of a new (third) wave of Covid-19 since July 4. He has named this metric as “Daily Death Load” (DDL) of Covid-19. He calculated the DDL metric every 24 hours from TOI data.
To calculate the metric on the progression/degression of Covid-19, Dr Srivastava took the ratio of the number of Covid-19 deaths in a period of 24 hours, i.e. while going from day D to day D+1), and the number of new active cases added in the same period of 24 hours. This number can be positive as well as negative and can take a range of values, small as well as large. It is negative when the number of recovered patients in 24 hours exceeds the number of new cases added in the same 24 hours. A favourable situation would arise when the daily death load is small and negative. “When I plot this ratio as a function of time I find that it exhibits wild fluctuations whenever there is a crossover from one scenario to another in the plot for the number of daily covid deaths,” Dr Srivastava said.
Explaining further, the former Pro-VC said even when the number of deaths was very high in May 2021, the DDL fluctuated wildly in a 10-day period from May 6 to 17, signalling that a crossover was in the offing. While the number of daily deaths was still very high and was fluctuating rapidly, the DDL had calmed down and attained favourable negative and small values. This marked the decrease in the daily death numbers.
The important point is that the DDL had signalled the onset of the second wave as early as the middle of February. Since July 4, the DDL has been fluctuating — so far it has been in the range 0.51 to minus 0.855.