COVID-19: tests, technology and the truth

As scientists at Pfizer and Moderna announced the rollout of the world’s first anti-coronavirus vaccine and the Ghanaian government declared airport tests free for young children, a minister reviewed the science and practical thinking behind arrangements for shielding Ghana from imported infection

The government’s move to ease access for families to COVID-19 tests at the country’s main point of passenger traffic with the rest of the world gives cause for cheer, is a useful complement to the existing arrangements, and should reassure Ghanaians that the regime in place offers value for money.

Public health officials at Kotoka International Airport in Accra have been using the antigen test since KIA reopened on 1 September. They are using the antigen, unlike the rapid diagnostic test (RDT) which looks for antibodies.

Most RDTs are cheaper because all they do is detect the presence of antibodies. The antibodies don’t tell you whether the person has the virus at the time of testing. Their presence only establishes previous infection.

By the time one develops antibodies in the blood – usually within two to three weeks after infection – the virus will have cleared from the affected person’s system. What this means is that, even if you should detect antibodies, you might be two to three weeks late in identifying an infected person, who will have been up and about infecting other people.

The value of an antibody test in stopping or restricting the importation of the virus is limited, if not non-existent.

Highly skilled work

It is for this reason that Ghana chose the antigen test. An antigen test identifies the causative organism or infectious agent: in this case, the SARS-CoV-2 virus. A PCR test is a form of antigen test because it identifies the virus: in this instance, the antigen.

It does so by allowing for extraction of the nucleic material of the virus – the ribonucleic acid, or RNA – and then amplifying the sequence extracted. It is cited as the gold standard for viral testing because, apart from confirming the presence of the virus, it gives you the arrangement or sequence of a part of the virus. A collection of many sequences gives you a genome, which is a complete map or make-up of the virus.

This laborious process of extracting the viral RNA and then amplifying demands skilled personnel and various chemicals to allow for extraction. The process takes between one and six hours. All this has been compressed into a procedure using the portable machines provided for what is being done at Kotoka International Airport. The procedure is called the fluorescent immunoassay antigen test. This has a specificity rate good enough to pick up anyone entering Ghana with the virus.

The system was benchmarked to the PCR output using COVID-19 samples worked on by our esteemed Noguchi Memorial Institute for Medical Research (NMIMR), with supervision from Professor William Ampofo, and was found to be highly sensitive. So here we are, getting test results that are of tremendous accuracy and which, better still, provide a turnaround time (the time that elapses between taking a sample and getting the result) of between 15 and 30 minutes.

Now just compare the value of US$150 with no delays at the airport to $75 with 24 to 48 hours of waiting time plus hotel bills, as is the case in Rwanda. Or choose between the $150 in China for a PCR test, which comes with six hours of waiting, and the no extra hours with immigration formalities at our airport. What about the previous arrangement, which made all travellers coming in to Ghana pay for two weeks of hotel bills, as well as endure two weeks of waiting and doing nothing? Which is more cost effective? Even if you pay $50 a night, that is $700 for 14 days.

Now, as of this week, children between the ages of five and 12 are able to enter the country without paying for a test. Children under the age of five remain exempt from testing.

By the way, I just spoke to a lawyer in quarantine in Ghana who asked that I assist him to get tested, even if it costs him $200, just so that he can go home. He insisted that the time he is spending in quarantine is a lot of money lost. He quoted $200 as how much he paid in the United States to get a PCR test done.

Cheap is not always effective

I have heard some people say there are antigen tests which cost $5. The last time I checked, a company in the US had or was in the process of developing an antigen test that would rely on the testing card. It is this diagnostic kit, from a US company called Abbott, that an article by Andrea Kane for claimed cost roughly $5.

The test kit uses no analyser; results are read directly from the testing card. The technology and mechanism are different from those for the fluorescent immunoassay antigen test for COVID-19 in use at Kotoka Airport. Although both are antigen tests, because the regimes use different technologies and biochemical configurations, their sensitivity and specificity will also differ, and the same will apply to cost or price.

At the end of the day, it is emerging technologies that are being priced and, just as occurs in the communications, automobile and other industries, new technology comes at a price, especially when associated with speed and accuracy. A Kia Picanto might resemble a Mini Cooper in size, but price-wise they are two different machines. It has taken millions of dollars in investment to come up with the technology we are using for our COVID-19 testing, and yet, with the announcement this month of the discovery of an effective vaccine against the disease, the infrastructure for testing at the airport will soon make itself redundant. Such is the enormity of the risk in such areas of work, where a discovery can make your service redundant and jeopardise the ability to recoup capital invested in research, development and delivery.

We had a choice as a country to go for a cheap, rapid test that might allow people to slip in to Ghana with the virus, or to choose a specific, sensitive test, comparable to the conventional PCR in its reliability, and yet quick enough to avoid the hotel lodging practised in Rwanda and elsewhere while awaiting PCR results. The cost of having just one more imported case of COVID-19 in Ghana is too high to allow for compromises with the rigour of our testing regime. The impact and cost of severe illness, debilitation and death are unquantifiable; all the more reason why I consider $150 for a regime based on a modern, sophisticated and extreme precision testing kit as a fair price.

It is the traveller who pays for the test, an arrangement which ensures that we save taxpayers’ money while guaranteeing the safety of Ghanaians against importation of the virus.

The alternative to the charge could be a renewed spike in our COVID-19 figures, more sick people, more deaths, the closing down of businesses and a knockout to millions of livelihoods. The alternative is too grave to contemplate.

Bernard Okoe Boye

Bernard Okoe Boye is the MP for Ledzokuku in Accra and a deputy minister of health

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