Trace and Test. This is a term that has become popular since March this year, when the Coronavirus hit our shores. Sri Lanka has so far detected around 35,000 Coronavirus patients (the vast majority of whom have since recovered fully), but that is only half the story. It is extremely important to find those who have come into contact with an infected person, however remotely. Apart from the immediate family members, any person can come into contact with hundreds of others in the course of one week.
This laborious and thankless process is called contact tracing. This would have been impossible without the relentless efforts of our heroic Intelligence Officers, who laboured 24/7 to find the contacts of every one of the infected persons. They could even find the contacts of patients in Galle from Jaffna and Mullaitivu. One can imagine the sheer logistics involved.
But once such contacts are identified, the next step is to test them. This is the only way to check whether they themselves have become infected as a result of moving closely with the original infected individual. To date, the authorities have conducted nearly one million Polymerase Chain Reaction (PCR) Tests to identify infected persons countrywide.
The PCR is known as the Gold Standard Covid-19 Test, with accuracy close to 100 percent. This test actually detects RNA (or genetic material) that is specific to the virus and can detect the virus within days of infection, even from those who have no symptoms. The test can be done in a clinic or a hospital. Turnaround time is longer, generally in the 2-3 day range but results can be in as early as 24 hours.
The main benefit of PCR tests is that they directly detect the presence of an antigen, rather than the presence of the body’s immune response, or antibodies. By detecting viral RNA, which will be present in the body before antibodies form or symptoms of the disease are present, the tests can tell whether or not someone has the virus very early on.
PCR gives us a good indication of who is infected. They can be isolated and get in contact with people they have been in touch with so they can be quarantined too. That is the true advantage of the diagnostic test - you can break that transmission chain and get a clearer picture of what is happening. In fact, this is exactly what the Government has done. While some are still in Forces-run quarantine centres, many more are in home quarantine, where they are not supposed to go out of the house or invite outsiders in.
While PCR tests are the gold standard, they may not always be practical if results are needed quickly. Enter the Rapid Antigen Tests. Rapid antigen tests are commonly used in the diagnosis of respiratory illnesses. In this case, the rapid antigen detection test looks for proteins produced by the SARS-CoV-2 virus, which is the virus that causes the disease called Covid-19. Antigen tests are immunoassays that detect the presence of a specific viral antigen, which means they identify people who currently have a viral infection.
While not as accurate as PCR, it can give correct results most of the time, with much less expense. The WHO South-East Asia Regional Office and WHO Sri Lanka recently supplied 100,000 rapid antigen detection tests to support Covid-19 surveillance activities in Sri Lanka. An additional 100,000 will be provided in upcoming weeks and a number of private companies too have imported the antigen test kits.
This is good news, as Sri Lanka urgently needs to expand testing. It is one of the few countries that does not yet offer walk-in testing. ‘Test, test and test’ is the mantra of those who battle against the virus. While testing is available for a fee at some private hospitals, this is not so well known. Those who can afford the payment (Rs.5,000-,6,000) should be encouraged to get tested this way as well.
In this context we commend the authorities for conducting antigen tests on the borders of Western Province from Friday. This will apply to passengers leaving through the Southern Expressway and other exit points of the Western Province ahead of the Christmas holidays. This will enable the authorities to identify any Covid-19 affected individuals and prevent their entry to other provinces, which are relatively Covid-19 free.
The next step should be to allow the private sector to import at-home antigen-based Coronavirus test kits, several of which have been approved for home use by the relevant global authorities. These allow people to test in the comfort of their own homes, but still report the results to healthcare providers.
All these tests cost under Rs.10,000, and are highly accurate and will take the testing burden out of the Government to some extent. For example, the Ellume home test kit manufactured by an Australian company (priced at US$ 30 or around Rs.5,600) calls for a nasal swab collection which can then be plugged in to a small single use cartridge and the result (positive or negative) is then transmitted via Bluetooth to a compatible Smartphone app, which can integrate with a country’s health service.
This way, any positive persons can immediately self-isolate, report their status and seek treatment. Furthermore, Sri Lankan scientists and companies too should be encouraged to manufacture such units for home use to save foreign exchange and uplift our scientific innovativeness. But regardless of the results, we will still have to follow health and safety guidelines under the ‘New Normal’ conditions for a few more years.