ANTIGEN assays, much faster and cheaper than the gold-standard reverse transcription polymerase chain reaction, or RT-PCR, tests, appear to have failed to catch on in COVID-19 mitigation because of an inexplicable unwillingness of the government. The government started COVID-19 infection test in the third week of January, with positive cases being first reported on March 8, in the only laboratory at the Institute of Epidemiology, Disease Control and Research in Dhaka. The number of laboratories gradually increased to 140, with 47 per cent of them being located in Dhaka that tests 62 per cent of the cases. Sixty-three of the laboratories are, however, in private hands. But neither the number of tests has significantly increased nor testing facilities have been expanded to cover the entire country as 30 of the 64 districts still do not have any laboratory that can run tests for COVID-19 infection. It is in this context the government rolled out antigen assays in 10 laboratories in 10 districts on December 5 and the number of laboratories to run antigen tests increased to 29 in 28 districts on December 18. Yet, the number of antigen tests has remained deplorably low, with 1,235 so far having been administered in three weeks, while 15,878 RT-PCR tests were run in 24 hours till Wednesday when only 54 antigen essays were administered.
Fifty-four antigen tests in 29 laboratories come down to less than two tests in a laboratory a day although, a health services official says, the government has the capacity to run tests on more than 50,000 samples, using both RT-PCR and antigen tests, a day. But the government is not willing to increase the number of daily tests that could arm up health managers and policy-makers to work out a better strategy for COVID-19 mitigation by way of a better understanding of what the current situation is. This appears to be more pertinent at a time when a probable second wave of COVID-19 infection is feared. While virologists think that the number of antigen tests should be increased, a number of civil surgeons and district hospital superintendents say that the Directorate General of Health Services has directed them to run antigen assays only in emergencies and on ‘very highly suspected cases’. When scaling up RT-PCR test is difficult, antigen assays can help to keep the outbreak at bay as they can be rolled in a large number and can identify people at great risk of spreading the disease. Antigen assays are said to have issues as they require a higher viral load, but anyone showing symptoms but testing negative with a rapid antigen test are advised to get a RT-PCR test.
Yet, rapid antigen tests constitute a key element in the testing strategy and in working out a better COVID-19 mitigation scheme. The government must, therefore, employ both the methods in a larger number for an effective understanding of the infection situation. The government should also roll out antibody tests, which detect the body’s immune response to the virus, to establish if anybody has already been infected and recovered for an import input in the mitigation strategy.
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