The Indian Council of Medical Research on Tuesday dismissed media reports based on a survey that showed that about one-third of the people living in containment zones and hotspots may have already been infected with Covid-19 and may have also recovered.
These findings related to the ICMR Sero Survey for Covid-19 are “speculative and survey results [are] yet to be finalised”, India’s nodal testing agency said on Tuesday morning in a tweet.
The survey had claimed that the spread of the infection was so widespread in some districts that even containment efforts had failed to curb the outbreak, The New Indian Express reported on Tuesday.
The report showed that around 15% to 30% of the population living in containment zones and hotspots had been exposed to the infection, an official told the newspaper, adding that these findings have been shared with the Union cabinet secretary and the Prime Minister’s Office.
“What we have understood so far is that the infection is much more widespread than what is reflected by the reported cases in many cities and containment efforts may not have fully paid off,” an official of the medical body said. “In tier II and tier III cities, on the other hand, the spread of the virus is minimal.”
The exercise was done in collaboration with the Department of Health and Family Welfare, the Centre and the National Centre for Disease Control. It was also supported by state health departments and key stakeholders, including the World Health Organization. The ICMR had earlier said the survey will help ascertain if there has been community transmission of the respiratory disease in areas with clusters of Covid-19 cases.
About 24,000 samples were collected in 70 districts of 21 states and Union Territories at random in what is called a “sero-survey”. These included ten hotspot cities – Mumbai, Ahmadabad, Pune, Delhi, Kolkata, Indore, Thane, Jaipur, Chennai and Surat – that contribute nearly 70% of India’s total caseload. In each of these cities, 500 samples were collected from ten randomly chosen containment areas.
In addition, 400 samples each were collected from the remaining 60 districts, which were categorised as high, medium or low, on the basis of the spread of the infection. Data for eight districts is still being analysed and will be added in the final report.
“Barring two hotspot cities Surat and Kolkata and six other districts, we now have results from all other sites,” an official told the newspaper. “It shows that infection size in many containment areas of the worst-hit districts is 100 to 200 times higher than the [overall] cases reported at those sites.” These sites are mainly in Mumbai, Pune, Delhi, Ahmedabad and Indore.
The tests were done to ascertain whether an individual has developed antibodies against the infection even though they are asymptomatic or show mild symptoms. Immunoglobulin G, or IgG, is a common type of antibody, which protects the body against infection. It usually appears 14 days after the infection and continue to be present in the blood serum for months. The presence of these antibodies simply means that the person had been exposed to the coronavirus but has recovered.