Covid-19: Tests soon to gauge immunity levels

Mumbai: The health ministry and the India Council of Medical Research (ICMR) are set to launch a survey to determine how many people in the country have developed immunity to the SARS-Cov2 virus.

In the initial stage of the population-based serological survey, blood samples will be collected from 800 individuals from each of the selected districts to study the extent to which Covid-19 has spread undetected across communities, gender and age groups, said officials.

The survey will focus on high-risk groups such as healthcare professionals and on low-risk individuals such as those without fever and pregnant women.


The states conducting the survey have been instructed that the samples collected will not be used for diagnosis of individual patients. In addition to throat or nasal swabs, blood samples will be collected for detection of IgG antibodies using the Elisa testing. As the survey expands, IgG Elisa-based testing of serum samples will replace the RT-PCR based testing.

Sero tests have become an indicator for governments across the world to determine the way forward in terms of implementing public health strategy.

For instance, the United States announced its surveillance study on April 10.

In a statement, Anthony Fauci, the chief scientist who is leading the country’s fight against Covid-19, said the study would give the country a clearer picture of the true magnitude of the pandemic by revealing how many people in different communities have been infected without knowing it, because they had a very mild, undocumented illness or did not access testing while they were sick.

In New York one study found 14-21% of the population had developed antibodies against the disease.