Pune-based National Institute of Virology has developed an immunological assay — enzyme-linked immunosorbent assay (ELISA) — that can detect antibodies that are developed in response to the coronavirus infection.
Health minister Dr Harshvardhan said this the first test of the kind to be developed in India and it will play a critical role in surveillance of proportion of population exposed to the virus. The NIV is the science cell of the Indian Council of Medical Research.
The mechanism for ELISA tests, which is routinely used for detecting HIV infection, is similar to rapid antibody tests as it looks for antibodies in the blood to ascertain if one has been infected with the coronavirus or not.
While ELISA tests for coronavirus are already available in other countries, procuring them in large numbers has been a challenge.
The company that has been licensed to manufacture the ELISA test will have about a month to make the tests available.
The development of these tests is crucial as the Indian Council of Medical Research can now conduct a study in 75 affected districts across the country to identify people who were exposed to the novel coronavirus infection and yet showed mild or no symptoms.
The study was to start last month, but was postponed as it was planned to be conducted with the rapid antibody test kits brought from China, but those test kits showed inaccurate results and were returned after a lot of controversy.
The exercise will also help ascertain if there has been community spread of the disease, officials said.
As part of the study, 30,000 blood samples will be taken randomly from people in the general population in the 75 hotspot districts.
"As a part of the study, people from red, orange and green zones in a district will be tested for COVID-19 at random to check whether they have developed antibodies against the infection even though they remained asymptomatic or showed mild symptoms,” said an official.
"The presence of antibody in them will establish that they were infected by the virus and were able to fight it off. They did not know they had contracted the disease as they had no symptoms," the official explained.
Districts with high population and heavy inter-state movement of people will be selected for the study to represent the respective state, the sources said. According to a study, around 80 per cent of coronavirus infected people show mild or no symptoms of the illness.