NEW DELHI: India may have over 1.32 lakh coronavirus patients as on Monday -- nearly seven times the official figure of less than 18,000 cases. This is as per a calculation based on age-specific infection fatality rates and deaths reported in the country so far.
The calculation has been developed by two German scientists who have estimated the overall mortality rate due to the infection in India to be 0.41 per cent -- much less than the official figure of over 3 per cent.
These scientists have estimated that only a small proportion of the people who are actually infected are getting tested and thereby getting detected with the disease in India, a trend in line with most other countries.
The study has assessed that only 6 per cent of the actual COVID-19 cases are detected globally and this figure varies significantly across countries. The detection rate in India could have been less than 17 per cent on March 31, it said.
The calculations developed by the researchers associated with the University of Gottingen have relied on another research by the Imperial College, London -- published in The Lancet Infectious Diseases journal -- which found that only two datasets of detection of COVID-19 cases were actually truly representative of the population anywhere.
These were of passengers on the cruise ship Diamond Princess and of all foreigners who returned from Wuhan in different countries, all of whom were tested for COVID-19.
The study analysed these datasets to determine age-specific mortality rates for COVID-19 and also revealed that the actual number of cases is way higher than cases detected in most countries. This is because nations have restricted testing to mostly symptomatic people, those who have come in contact with an identified confirmed case or those with a history of international travel.
"The daily reports of numbers of cases and are not particularly revealing because there is currently no representative testing anywhere in the world," said the paper by the German researchers.
The researchers took age-specific mortality rates to calculate the expected mortality rate in 40 other countries with significant outbreaks, including India. Based on the population structure in our country, they estimated that the overall death rate here due to the infection could be just around 0.41 per cent -- only marginally higher than seasonal flu.
"For most developing countries, the mortality rate is below 0.5 per cent.. while it is significantly higher for countries like Italy and Germany that have higher older age structure," the researchers noted.
The study also examined the period of time from the start of the first symptoms to death and estimated that those who succumb to the infection take 18 days on an average.
"Given a few days between the start of infection and diagnosis would mean that death rates on a specific date would reflect infection figures two weeks ago," the study said.