Explainer: Why home Covid test kits are useful – but not yet popular in India

Self-test kits are being widely used in many Western countries with the Omicron variant of the coronavirus driving a surge in Covid-19 cases. In India, on the other hand, the use of self-test kits has been subdued so far.

But as cases start to rise again, though not as dramatically as in other countries, the sales of self-test kits in India have increased in December, data collated from various manufacturers and pharmaceutical portals shows.

Experts say these kits are a useful tool for mass screening of Covid-19 as they provide results within minutes at a lower cost. Before the pandemic, the concept of a self-test in India was largely restricted to confirming a pregnancy and checking blood sugar levels. This is the first time a self-test for a disease is available in India.

Epidemiologist Dr Srinath Reddy said that “the whole idea behind self-test is to quickly detect and isolate an infected person”. “People who have been exposed to an infected person or have symptoms should take this test if they don’t want to visit a lab,” he said.

Which test to choose?

A self-test gives results within 15-30 minutes. Most self-testing kits employ rapid antigen testing, in which a nasal swab sample is taken and tested to detect proteins which are present on the virus surface.

The detection of proteins will mean the sample is positive for coronavirus. Self-test kits have an extraction tube, sterile nasal swab and a testing card. A person has to insert the swab stick into their nose, 2-4 cm deep, and scratch the back of the nose to collect a swab.

This swab stick is then swirled in an extraction tube to allow it to mix with the liquid inside and a few drops from the tube are tapped onto a testing card. The card then gives a positive or a negative result.

Some newer tests deploy an easier technique and detect the virus in saliva. A person has to spit into a tube. This is tapped onto a testing card and the virus is detected within 20-30 minutes.

In India, Pune-based Mylab’s kit was the first to be approved for self-testing in May. Its CoviSelf kit uses an antigen test to detect the virus. In the last eight months, six more kits have been approved by the Indian Council of Medical Research.

These include PanBio by Abbott, CoviFind by Meril Diagnostics, Clinitest by Healgen Scientific Limited, ULTRA Covi-Catch by SD Biosensor, AbCheck by Nulife Care and Angcard by Angstrom Biotech. At least three more manufacturers, Pathkits Healthcare, Trivitron Healthcare and Oscar Medicare, have applied for validation with the Indian regulator to market their kits.

For those who cannot bear the discomfort of inserting a swab stick into their nose, the saliva test is an easier option. Currently India has only one manufacturer, Angstrom Biotech, for saliva-based rapid testing.

The real-time polymerase chain reaction test, or RT-PCR, remains the gold standard for detecting Covid-19. Unlike antigen tests, it amplifies the ribonucleic acid, or RNA, in the virus and has a better chance of detecting it, although it takes several hours to produce results and is more expensive. Also, unlike RT-PCR reports, self-test results are not yet accepted for domestic or international air travel.

Instant results, smaller queues

In India, a self-test could be a game changer in managing the pandemic if people are able to get tested quickly at a low cost and immediately isolate themselves. It would also cut queues outside laboratories, reduce costs and dissipate the burden on the existing manpower to collect samples from homes, say public health experts.

A research letter in the Journal of the American Medical Association in August stated that “frequent at home testing can prevent viral transmission in in-person work environments or other social settings”. Self-tests can be useful in case of large social gatherings or corporate offices for routine screening. The Centres For Disease Control and Prevention in the United States said self-tests act as a “risk reduction measure” along with masking, physical distancing and vaccination.

“It’s a good surveillance tool, provided it is done correctly and frequently. For that, it must be simple and inexpensive,” said virologist Dr Shahid Jameel.

In the United Kingdom, anyone registered with the National Health Service can order self-tests online or pick them up from a pharmacy for free. In India, though, the cost per kit varies from Rs 220 to Rs 500 depending on the brand. Jameel said fewer people will opt for self-testing if it is chargeable. “It will only be used in institutional settings then,” he said.

The complexity of such tests for a first-time user is also a major reason why semi-urban and rural regions, with lower literacy rates, have seen a lower demand for these kits as compared to metro cities. Reddy said demonstrations are necessary in local neighbourhoods to help people understand how to perform a self -test.

Few false negatives

The sensitivity of an antigen test to detect the virus is around 65%, lower than the RT-PCR test which has an 85%-96% sensitivity. Despite lower sensitivity, antigen tests are a great mass surveillance tool because they produce results within 15-30 minutes and require no equipment.

A major drawback is that an antigen test has a high chance of missing a positive case if the viral load in an infected person is low. An antigen test, that most self-test kits use, does not amplify the RNA of the virus and has lower chances of detecting it.

This means that a negative test result does not necessarily mean the person is not infected. While an antigen test has low sensitivity, it has high specificity which means it rarely mistakes a negative case as a positive case.

Reddy said if a person is symptomatic, they should continue to isolate even if they test negative through a self-test. “In some cases, a person with low viral load may test negative in an antigen test. He can re-test himself with RT-PCR if he continues to have symptoms,” said Reddy.

India sees rise in sales

Manufacturers said from July to October, the demand for self-testing kits was low due to a dip in the caseload in India. In November and December, sales picked up with the Omicron variant driving a global surge in cases. This has pushed corporate offices to opt for routine testing.

Mylab noted a rise in sales by 95% in November compared to October and a 190% jump in sales in December compared to November. Maharashtra, West Bengal, Rajasthan, Delhi and Andhra Pradesh remain the top states where the demand for such kits remains high, a company spokesperson said. “In Maharashtra, we saw 185% more sales than the previous month. Mumbai followed by Delhi and Kolkata are the biggest buyers of self-test kits,” the spokesperson said.

According to Mylab’s internal study, first-time users found the process of self-testing challenging. The company plans to raise awareness on the use of the kit in tier-II and tier-III cities. The difficulty in learning how to use a self-test, at least in non-metros, has kept domestic sales low.

Nulife, which manufactures AbCheck, has the capacity to produce 1.25 lakh kits per day. Jareer Ahmed, head of sales and marketing, said the company received approval in India three months ago but domestic sales form a small percent of total sales. “In India, mostly corporate offices buy our kits. The demand has risen in the last 10 days by five times but it is still low in absolute numbers,” said Ahmed.

The AbCheck kit has a greater demand in foreign countries with Ireland, Thailand and Malaysia already in touch with Nulife to import the self-tests. Ahmed said they hope the demand will further rise in the domestic market in the coming days.

Meril Diagnostics, which can manufacture 20 million kits per month, is also anticipating a growth in demand in India. Sanjeev Bhatt, senior vice-president, corporate strategy, Meril, said they have noted a 50% week-on-week increase in the demand for the kits across online portals and offline distribution channels. “This rise has been seen in light of the new variant. We have seen this noticeable upsurge in demand across key urban metros, owing to increased awareness about such testing methods,” said Bhatt.

“This can also be attributed to the working population, with many adopting such proactive, preventive measures to ensure the safety of their loved ones as they resume work in office settings,” Bhatt added.

Dhiraj Jain, vice-president managing supply chain operations at Pharmeasy, said the current trend for self-testing is limited to metro cities because “self-testing kits are not massively promoted”.

Pharmeasy has stocked up on self-test kits for the next five to six months. The portal has noted a five-time increase in sales in December compared to the previous month. Maximum sales, though, are limited to online portals, not chemist shops. Prasad Danave, president of the Retail and Dispensing Chemist Association, said retail chemists are not stocking self-testing kits. “We are not getting a lot of requests,” said Danave.

In India, the Indian Council of Medical Research has mandated that all manufacturers create a mobile application where each person taking a self-test has to enter the result, which is then synced with the Council’s portal. A manufacturer said the current test positivity rate of self-test kits is less than 1% in India. All positive and negative results are entered on the Indian Council of Medical Research portal.

This reporting was supported by a grant from the Thakur Family Foundation. Thakur Family Foundation has not exercised any editorial control over the contents of this article.