The Indian Council of Medical Research (ICMR) has asked states to conduct a large-scale surveillance to establish the extent of exposure to the COVID-19 infection in specific groups of people, or in the high-risk population areas. ICMR has notified that it has advised states to conduct ‘sero survey’ to measure the coronavirus exposure in a population by using the IgG ELISA test.
In this regard, ICMR has communicated a detailed plan to all the states for measuring the coronavirus exposure in general population and in high risk populations. ICMR has given an indicative list of people where the sero survey must be conducted. These groups include people who are at a high exposure to COVID-19 infection including healthcare workers, immune-compromised individuals, police officers, people residing in containment zones, migrant workers, press corps, industrial workers, air travel staff, and other such groups.
According to ICMR, sero-surveys help to understand the proportion of population which has been exposed to the SARS-CoV-2 infection including the asymptomatic individuals. Depending upon the level of sero-prevalence of infection, proper public health intervention steps can be implemented, which will lead to the prevention and control of the infection.
Sero-surveys are conducted using IgG ELISA test. The purpose of the test is to detect the presence of IgG antibodies in an individual, which represents a possible exposure to the COVID-19 infection. The immune system of a human body starts developing IgG antibodies after getting exposed to SARS-CoV-2.
A doctor in India working on the frontline told The Federal that sero-surveys must be implemented as the survey will be of huge help in knowing the scale to which the pandemic has penetrated in a particular locality. He added that the results of the IgG ELISA tests conducted as part of the sero-survey will have a direct impact on the case fatality rate.
For conducting the sero-surveys throughout the country, ICMR has transferred the technology to several pharma companies for the fast track production and increased availability of the IgG ELISA test kits. However, real time RT-PCR test is the major frontline test for the clinical diagnosis of SARS-CoV-2, causing COVID-19. This test is useful only when conducted in the acute stage of the infection (< 7 days)
— ICMR (@ICMRDELHI) May 31, 2020
As of May 31, 2020, the total molecular based samples conducted across India is 37,37,027. In the last 24 hours, 1,25, 428 samples have been conducted. So far, the total number of COVID-19 cases detected in India is 1,65,799 and 4,706 people have succumbed to the infection.