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COVID-19: Why does testing matter?
By Paul Hinckley, Occupational Health Advisor at Staywell Occupational Health – 3rd April 2020
At the present time, as Coronavirus continues to spread, and more cases of COVID-19 (the disease caused by the virus) are reported, the UK has been criticised for its slow response in testing more individuals.
At the time of writing, testing is not yet widely available for most people. The small number of tests available are being reserved for critically-ill patients and front-line NHS staff, with much of the actual test samples from these essential key workers being collected at temporary “drive-through” facilities, sited in the car parks of what were once thriving retail outlets.
It is hoped that, as more numerous and less-complicated methods of testing become available, testing can be offered to other key workers upon which the smooth running of the UK infrastructure depends. Ideally, in time, the test will be available to everyone.
What is the test?
The test is able to check for, and confirm the presence of, signs of COVID-19 genetic material. It looks for certain types of human immunoglobulin, or antibodies. These are complex proteins formed in our blood, and are an essential part of our immune system, enabling it to fight off both bacterial and viral infections.
Why is this information important?
Testing can discover the presence of two specific COVID-19 immunoglobulins: IgM and IgG. The detection of COVID-19 IgM antibodies in an individual tends to indicate a recent exposure to COVID-19 (possibly at a time when the individual is incubating the infection and will be contagious to others), whereas the presence of COVID-19 IgG antibodies will indicate that the disease was contracted some time previously, and therefore the individual will be towards the end of the infection phase and may even have already developed immunity.
Despite the relatively high number of deaths so far, for most people COVID-19 will be a mild to moderate infection from which they will make a full recovery. Testing will provide evidence that the individual has either already been exposed to the disease in the past, has gone through the incubation period, recovered and developed immunity, or that they are fighting a current infection. In other words, it will tell us who currently has it and who has previously had it.
This is why the UK government and Public Health England guidelines about self-isolating for 7 or 14 days (if you are symptomatic, and depending on your living arrangements) have been, and still are, so crucial in protecting ourselves from the spread of this infection. These timescales are relevant to the incubation period of COVID-19, and until now, it has been guesswork as to whether the disease has actually been present, or whether it was another type of seasonal influenza or other chest infection.
Testing will eliminate the need for guesswork in diagnosing COVID-19, and testing positive is good news, assuming a full recovery is achieved, as this means that individuals within this group can then safely return to working in what are very often critical key roles, and can then confidently support those who require it in our health and care system. Having this information may be instrumental in changing the rules on lockdown and social distancing, and it will also identify those who remain vulnerable (i.e. those who test negative), so that extra planning can be made around the need to potentially treat them, especially in critical care environments.
Can I get tested?
At the moment, there are some fairly complex, expensive tests available that require a swab from the nose or throat to be taken and then tested in a laboratory. Understandably, these testing methods are reserved for seriously ill hospital patients, and the front-line staff who are caring for them.
This means that unfortunately the majority of people who have had symptoms and have followed the guidelines to self-isolate (or for those vulnerable because of pre-existing underlying health conditions and who must therefore shield for 12 weeks) will not yet know for sure if they are currently infected with COVID-19, or indeed have previously contracted it and have recovered.
However, new antibody tests have been developed to test for IgM and IgG, and these will be available across a wider range of the population in the near future. These tests involve taking a small drop of blood from the fingertip and applying it to a test strip. No laboratory equipment is required, and the results can be available in fifteen minutes. At the moment, these must be administered by a qualified healthcare professional, but it is almost certain that home testing kits will eventually become available to individuals on a commercial basis. Those who test negative using these methods should re-test again seven days later.
Why isn’t the UK doing more tests?
Essentially this is down to not having the resources to undertake mass testing at the moment. This has been explained by a national shortage of swabs, test kits and reagent, the chemical used to extract the genetic material from the sample. Greater global demand has created a national shortage, and there has also been a limited number of laboratories in the UK that so far can carry out testing.
Steps are being taken to increase production, of these items, and of the test kits described above that eliminate the need for laboratory analysis.
Looking at the International graph below, those countries that are ahead of the UK in the race to test their population essentially had greater stockpiles of testing material at the beginning of the pandemic, and also have greater testing capacity. South Korea, for example, despite having a slightly smaller population compared to the UK, has twice as many labs and about two-and-a-half times the weekly testing capacity when compatred to the UK at the current time.
It’s important to note the date of this article as, in keeping with the dynamic, ever-changing nature of this pandemic, the numbers are sure to change again very soon.