The Indian Council of Medical Research (ICMR) is on the verge of completing its second national sero survey to check the coronavirus disease (Covid-19) prevalence in the country. The results of the sero survey would be made public by the end of September, said Dr Balram Bhargava, director-general, ICMR .
“The second national sero survey is almost done. We have completed the exercise in 68 out of 70 districts, and the analysis is in progress. We should have the results by the end of September,” said Dr Bhargava.
“Sero survey tells us about the prevalence or trend of the Covid-19 pandemic in a particular area. One sero- survey alone will not be enough. If you will look at the Geneva sero survey, they did it for five weeks. The findings were published in Lancet, but they did not show many changes. The National sero survey, which was conducted in April and May, is being repeated after three months,” he added.
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The sero survey also seeks to determine the infection fatality rate (IFR), a key component of the exercise, said Dr Bhargava.
“If you look at the results of the National sero survey, which was conducted in April and May, the IFR was between 0.5% and 0.6%. The IFR was much lower than Europe and the United States of America (ISA) that have an IFR ranging between 1.2% and 1.8%,” he said.
The findings of the first national population-based sero survey indicated that 0.73% of adults in India were exposed to SARS-CoV-2, which causes Covid-19. The blood sample is tested to check for the presence of antibodies against the virus.
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The data published on the first sero survey in the Indian Journal of Medical Research (IJMR) showed that an estimated 6.4 million people had contracted the infection around early May when swab samples were collected for analysis.
Based on the overall adjusted sero-prevalence of 0.73% and reported Covid-19 cases, it was estimated that for every Covid-19 case — determined by real-time polymerase chain reaction (RT-PCR) test — there were between 82 and 130 cases of contagion in the country.
The sero-prevalence ranged between 0.62 and 1.03% across the four strata of districts.