What’s “Feluda”, the Covid-19 Test that Everyone is Calling a Game-Changer?


What’s “Feluda”, the Covid-19 Test that Everyone is Calling a Game-Changer?

Illustration: Reynold Mascarenhas

“Test, test, test” was the mantra given by the World Health Organisation at the beginning of the pandemic to “flatten the curve”. From the first swab sample on January 23 to a few thousand tests a day to over one million Covid-19 tests, India has come a long way. However, given India’s dense and humongous population, testing will have to be further scaled rapidly to detect, trace and arrest the spread of the virus.

A paper-based Covid-19 test called “Feluda” named after Satyajit Ray’s famed detective,  developed by two Indian scientists could be the game-changer. “This is a simple, precise, reliable, scalable and frugal test,” Professor K Vijay Raghavan, principal scientific adviser to the Indian government, told the BBC.

Feluda was developed by Institute of Genomics and Integrative Biology (IGIB) scientists – Souvik Maiti, senior principal scientist, and Debojyoti Chakaraborty, senior scientist. The test is based on a gene editing technology called Crispr. Feluda would return results in under an hour, which is much faster than the current gold standard, the rRT-PCR test. When Feluda was tested on samples from about 2,000 patients, they found that the new test had a 96 per cent sensitivity and 98 per cent specificity.

The test is expected to cost ₹500, with the Tata Group handling the industrial and commercial operations of the kit. The nod for a commercial launch has been given by the Drug Controller General of India.

A highly sensitive test detects almost everyone that has the disease, whereas a high specificity will rule out almost everyone that doesn’t have the disease. India has so far been using the PCR test and the rapid antigen test. The PCR tests are reliable but cost ₹2,400 whereas the antigen tests are cheaper but generate more false negatives. Many experts believe that the Feluda test could potentially replace the antigen test because it is comparatively cheaper, and accurate.

“The new test has the reliability of the PCR test, is quicker and can be done in smaller laboratories which don’t have sophisticated machines,” Dr Anurag Agarwal, director of IGIB, told BBC.

The sample collection technique for the Feluda test would be similar to the PCR test, a nasal swab inserted a few inches into the nose to check for coronavirus in the back of the nasal passage. The Fedula test doesn’t require the machinery required for a real-time reverse transcription polymerase chain reaction and the skilled manpower required to use it. Standard PCR machines can be used, which are more readily available as well.

Two blue lines indicate a positive result, while a single blue line means the test has returned negative.

“India has the opportunity to show the value of this test, because it has such a big population and it’s coming right at the time when it is needed. If their efficacy is demonstrated, it can have benefits that ripple around the world,” said Dr Stephen Kissler, a research fellow at Harvard Medical School in the BBC report. “In the ideal world I envision, taking a test will be as easy as brushing your teeth or making toast,” added.

A cheap and reliable Covid-19 paper-test is an innovative and much-needed step in that direction. Something India desperately needs.