Why in news?
Rapid testing kits used to detect antibodies to the novel coronavirus have proved unreliable.
Why such kits are needed?
- Governments around the world are looking for an accurate blood test that can tell people if they have immunity through past Covid-19.
- The diagnostic RT-PCR test to confirm the presence of the virus using a nasal swab in a laboratory setting is considered reliable.
- The attempts to design a rapid test that uses a blood sample to find antibodies after past infection have been proved unreliable.
- They have missed about 30% of positive cases, showing low sensitivity.
What concerns many countries?
- The low sensitivity of the kit is the phenomenon that is worrying India.
- Many Indian States have already imported several hundred thousand rapid testing kits, mainly from China.
- India’s experience is shared by the US, UK, Spain and other countries.
- ICMR has advised States to use these kits for surveillance testing rather than to make medically important decisions.
What is the challenge now?
- Narrowing down the test to reliable methods is the challenge.
- The WHO is working to identify them and the results will be crucial.
- All countries are looking at sero-surveillance as a process that may determine the status of population on Covid-19.
- An exit from lockdown and other public health measures depend on such testing.
What should India focus on?
- India should remain focused on identifying tests that work well.
- This requires close integration with efforts launched by diagnostics regulators in the U.S., Europe and China.
- These countries have allowed early use of these kits, which themselves are under evaluation.
- Some vendors of rapid testing devices in China have run afoul of regulators since they have no prior expertise in the field.
- Therefore, making purchase decisions calls for rigorous review.
What should be done?
- In the immediate context, the message should go out to States that rapid tests cannot substitute for RT-PCR to diagnose infection.
- It is by no means clear that antibodies developed in response to COVID-19 provide long-term protection against re-infection.
- A good reliable test to certify that a large section of the population have developed immunity against Covid-19 is needed.
- These tests would be a promising tool to reopen the economy with confidence.
Source: The Hindu
