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The Indian Council of Medical Research (ICMR) received five lakh antibody rapid test kits for the novel coronavirus (SARS-CoV-2) — the first of three tranches — after three earlier deadlines expired.
The kits will be used to study the virus’s spread in a given area, not to diagnose, said R Gangakhedkar, who heads ICMR’s epidemiology division. “These tests will be conducted periodically in hotspots to monitor if infections are going up or down,” he said.
They are termed rapid as they yield results in hours, unlike other RT-PCR tests that take a couple of days.
That, however, should not make everybody rush for the new test, Gangakhedkar said.
The new kits check for antibodies — tools the immune system forms to fight a virus. These can be of two types: IgG and IgM.
The presence of IgM, which withers away in days, in a blood sample indicates a recent infection. The presence of IgG antibodies suggests a relatively older infection.
The five lakh kits include both types: those that can confirm the presence of IgG as well as IgM.
The specificity of these kits is 84 per cent. The higher the specificity, the lower the chances of yielding a ‘false negative’.
Antibodies usually develop in a body 14 days after the infection. So, if a person tests positive for them, does it mean s / he would never again be infected with SARS-CoV-2?
“It depends on the quality of antibodies. For instance, if one suffers from chicken pox infection and develops antibodies, s / he will never be infected again, However, if one suffers from the Human Immunodeficiency Virus (HIV), the antibodies do not prevent a further infection,” Gangakhedkar said.
In case of COVID-19, we need more research to suggest whether the antibodies are good enough to prevent a second infection,” he added.
The kits have been manufactured by Chinese firms Wondo Biotech Co and Zhuhai Livzon Diagnostics Inc.
The Union government, meanwehile, asked states to resume ante-natal check-ups and routine immunisation activities, according to Lav Agarwal, joint secretary at the Union Ministry of Health and Family Welfare.
Kerala notified to this effect on April 16. Many states, including Bihar, Rajasthan and Kerala, put them on hold when the nationwide lockdown started March 25. Health experts have warned long-term impact of doing so.