ICMR COVID-19 study: A third of containment zone population may have got infected, recovered unknowingly

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The Indian Council of Medical Research's (ICMR) first population-based serosurvey in India revealed that around 15-30 percent of people living in the containment zones in hotspot cities were infected by the novel coronavirus and unknowingly recovered, the New Indian Express reported.

The preliminary findings of the ICMR’s survey have been shared with the Union cabinet secretary and the Prime Minister's Office said the report citing government sources.

A serosurvey involves testing of blood serum of a group of individuals to determine the presence of antibodies against that infection to know who has been infected in the past and has recovered. In this case, the blood samples collected from individuals under a testing protocol were tested for the presence of antibodies against SARS CoV 2, the virus that causes COVID 19.

According to the report, the ICMR took help from the National Centre for Disease Control, the World Health Organisation's India office and the state governments to collect the blood samples. They had collected nearly 24,000 samples from 70 districts in the country from randomly picked individuals for the survey.

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Samples were collected from Mumbai, Ahmadabad, Pune, Delhi, Kolkata, Indore, Thane, Jaipur, Chennai and Surat that contribute nearly 70 percent of total COVID-19 cases. As many as 500 samples each were collected from 10 randomly chosen containment areas in each of these cities, said the report.

Also, 400 samples each from the other 60 districts across 21 states, categorized on the basis of the low, medium and high caseloads, were also collected.

The results from all sites, except Surat and Kolkata, showed that infection size in many containment areas in the worst-hit districts is 100 times to 200 times higher than the cases reported at those sites, an official familiar to the survey report was quoted as saying.

The sites where infection size is 100 to 200 times higher are mainly in Mumbai, Pune, Delhi, Ahmedabad and Indore, another official told the publication.

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