Coronavirus: India’s ambitious ‘test on demand’ approach is fraught with problems

By stating that “all individuals who wish to get themselves tested” are eligible for tests on demand, the ICMR is theoretically making all of India’s 1.3 billion people eligible for a test and also demand a test repeatedly without an upper limit, even when the country does not have the capacity to undertake such a massive exercise. Clearly, the latest advisory is over ambitious and has been framed without much application of mind.

On September 4, India crossed four million novel coronavirus cases, 13 days after crossing three million on August 22. On September 5, the 90,600 fresh cases reported surpassed China’s total recorded cases (90,025). On September 6, with 91,723 additional cases reported, India (4.20 million) surpassed Brazil (4.13 million) to record the second highest number of cases in the world after the U.S. (6.27 million)

Since the beginning of August, India has been reporting the highest number of cases each day, and this has been steadily increasing — from over 50,000 in early August to over 60,000 in the third week, over 70,000 in the fourth week before jumping to over 80,000 cases in September.

Large number of undetected infections 

Though the number of tests done each day has been over one million for the past week, the test positivity rate nationally is still high at 7.7%, clearly indicating that testing has to be ramped up sharply. Though the antibody tests used differ and the methodology adopted are not ideal, seroprevalence surveys carried out in a handful of cities clearly indicate that the number of infections is many times more than those detected. Also, considering 0.5% infection fatality rate, over 1,000 deaths reported each day for the past week suggests that there would have been about 2,00,000 infections 16-18 days ago, while only nearly one-third of infections were actually being detected.  

Though the number of tests performed each day by many States has been growing, nearly 50% of them are rapid antigen tests that have only about 50-60% sensitivity. Unfortunately, with no repeat testing of negative cases and only a small percentage of people with symptoms but negative results being validated with a RT-PCR, many infected people are not being diagnosed.

Test on demand

The latest advisory from ICMR provides for testing on demand to “ensure higher levels of testing”. While ramping up testing is much needed, testing on demand by anyone might not be the correct approach to adopt. By stating that “all individuals who wish to get themselves tested” are eligible for tests on demand, the ICMR is theoretically making all of India’s 1.3 billion people eligible for a test and also demand a test repeatedly without an upper limit, even when the country does not have the capacity to undertake such a massive exercise. While it is a welcome measure, especially in the private sector, the general fear about infection and other reasons might result in diverting some of States’ already-stretched health and financial resources if they have to test those who do not , on the face of it, require a test.

Clearly, the latest advisory is over ambitious and has been framed without much application of mind.

Detecting cases or reducing test positivity 

With States already not validating the negative results from rapid antigen tests with a RT-PCR, non-directed tests on demand might help more in increasing the number of tests carried out each day and hence reduce the test positivity rate than in early detection and containment of the virus. The focus must remain on diagnosing the most probable cases listed out by ICMR — those showing symptoms or belonging to high-risk categories.

Since a large proportion of infected people have mild or no symptoms, test on demand might be particularly helpful in detecting cases that might otherwise have been missed. But such a strategy should be restricted to clusters, hotspots, and containment zones besides dense urban areas with anticipated high transmission in the unlock phase.  Otherwise, States, which procure test kits on their own, will thus be forced to use their discretionary power to deny tests for people not exhibiting symptoms or belonging to low-risk categories or selectively charge for testing to pay for procurement of testing kits and to avoid additional pressures on the testing infrastructure. There is also the possibility of an over-reliance on antigen testing to cope with the increased demand for testing.

A more nuanced approach to testing guidelines is therefore necessary.

Published in The Hindu on September 8, 2020