Covid-19: ICMR asks States to carry out antibodies test on key exposed populations

Indian Council of Medical Research (ICMR) has advised all states and union territories to conduct sero-surveys, which are blood-based diagnostic tests to measure novel coronavirus (SARS-COV-2) exposure in varied populations.

ICMR has stated that these tests could possibly be carried out in key populations that include vendors and owners as well as staff working in grocery shops including those that sell milk and bread, pharmacists, restaurant staff, employees of banks, post, couriers and telecom offices, air travel staff, those staying in slums, old age homes, orphanages, homeless shelters and hostels, prisons, drivers, bus conductors, staff in municipal bodies working in sanitation, water and electricity supply, as also in farmers visiting large markets, migrant workers, journalists, police personnel, health care workers, individuals in containment zones, and patients with HIV, Tuberculosis, Severe Acute Respiratory Illness, Chronic Obstructive Pulmonary Disorder, patients on dialysis and so on.

ICMR has advised that blood tests should be carried out using Enzyme Linked Immunosorbent Assay (ELISA), which is traditionally also used in testing HIV and viral hepatitis. IgG ELISA test recommended by ICMR will test for presence of antibodies against SARS-COV-2 in the populations. “IgG antibodies generally start appearing after two weeks of onset of infection, once the individual has recovered from infection and last for several months. They are not useful for detecting acute infection but indicates episode of infection in past. It helps to understand proportion of population exposed to the virus including asymptomatic (persons without any symptoms) so appropriate public health interventions can be planned for the prevention and control of the disease,” the ICMR directive states.

The states must decide the number and frequency of tests they would want to carry out depending on requirement and situation in that particular area.

ICMR has stated that the indigenous kit it has developed has high sensitivity (ability to correctly identify actual positive cases) and specificity (ability to measure healthy people who do not have the antibodies against the virus), however it has not declared exact percentage of both these parameters.

ICMR has transferred the IgG ELISA kit technology to Zydus Cadila, J Mitra & Company, Meril Diagnostics, Voxtur Bio, Trivitron Health Care, Karwah Enterprises and Avecon Healthcare amongst other to fast track its production. “The technology has been transferred to various entities without exclusivity Clause and therefore can be shared by others as per demand and technology. Kits from other USFDA, CE-IVD, indigenous sources are also available” said an ICMR spokesperson.

ICMR has also stated that it will provide technical support to states and UTs who plan to carry out such sero-surveys, including interpreting test results.