A serological survey by the Indian Council of Medical Research or ICMR from 69 districts across 21 States in India found that an estimated 7,00,000 people could have been infected by SARS-CoV-2 in these districts even in early May.
Results from the survey suggest that the actual COVID-19 case count by early May could have been at least 20 times more than what was detected in India at that time.
A serological survey is when blood samples of the general population are analysed and incase specific anti-bodies are detected, they are labeled as infected with SARS-CoV-2 in the past.
In May, about 24,000 blood samples of adults were examined for antibodies produced specifically by SARS-CoV-2 via an ELISA test.
The test has been developed and validated by the ICMR-National Institute of Virology and is said to be the most reliable so far.
While the actual number of those infected was not disclosed, 0.73% of the population in these districts had evidence of past exposure to SARS-CoV-2.
The adult population of these districts according to the 2011 census works out to around 96 million persons.
If the results are applied to the adult population of these districts, the number of people likely to have been infected crosses 7 lakh.
This number is twenty times higher than the 35,000 confirmed cases as of early May in the entire country.
