Welcome to Naturally Speaking’s blog series on COVID-19. This second post is about Testing and Treatment. If we don’t answer all your most pressing questions, please feel free to ask them in the Comments section below – we’ll do our best to respond. We’ll also aim to provide any updates as advice and knowledge evolves. Click here to switch to the more complete version of this post (with extra details and links).
Disclaimer: Some of the guidance refers specifically to the situation in the UK, although most of the content is relevant regardless of where you hail from.
Q. How is diagnosis confirmed?
A. If a patient presents with any COVID-19 symptoms, they are generally treated as infected until proven otherwise. This is to minimise potential transmission. RT-PCR testing uses knowledge about the SARS-CoV-2 genetic code to test whether the sample from a patient (taken from the respiratory tract – a swab from the back of the throat or nose) contains the virus. This is being widely used to confirm cases. If there is a backlog of samples in the laboratories (as samples should be analysed ASAP but this is not always possible) or results are inconclusive , then clinicians are also using CT scans of the lungs to identify signs of the disease in more severe cases.
Q. What are the differences between RNA, antigen and antibody testing kits?
A. Using reverse-transcription polymerase chain reaction (RT-PCR), it is possible to test a patient’s respiratory sample and ascertain if they are infected with SARS-CoV-2 within a few hours by detecting RNA (genetic material) from the virus. Nonetheless, lab capacities and the extent of the pandemic has meant that the turnaround time for results is often longer than this. These are currently being used in healthcare settings to confirm whether patients have viral RNA. Antigen testing kits, on the other hand, will soon use blood samples to test for circulating viral proteins, and say whether the person is currently infected with SARS-CoV-2. This has the added advantage over RT-PCR of confirming the presence of live virus.
Antibody kits, on the other hand, test whether the person has previously been infected with the virus. This will be important to help understand whether those who have been infected can be re-infected and for how long immunity lasts. All three tests are important to eventually allow those who are self-isolating to only have to do so when necessary.
Q. Why are there so many criticisms regarding “lack of testing”?
A. From the beginning, the WHO has emphasised the importance of testing. Testing allows researchers to understand much more about the virus, from possible symptoms to transmissibility. Further, as the COVID-19 burden on the NHS begins to increase, staff shortages become more pronounced as many healthcare professionals are self-isolating. Testing NHS staff would allow those who are healthy to return to work. Currently, only patients in hospital presenting COVID-19 symptoms are being tested. NHS staff and other key workers will be prioritised once testing capacity increases. The public will want access to tests and the WHO advises that the best way to control COVID-19 infection will be to test as much as possible – this will better inform measures such as social distancing and other restrictions.
Prophylaxis & Treatment
Q. How do vaccines work?
A. Vaccines are control measures, used to prevent infection. They often contain antigens of a pathogen (surface molecules recognised by the immune system) which are introduced into the body in small doses. This triggers an immune response and can ‘train’ a person’s immune system to recognise a virus, which means that when re-infected with the same pathogen, the body’s immune system will be able to mount an effective defense much more quickly.
Q. What progress has been made towards the development of a COVID-19 vaccine?
A. Many companies and academic institutions are working towards a vaccine. Moderna Therapeutics, a Massachusetts-based biotech company, has already produced a vaccine called mRNA-1273. The US National Institutes of Health (NIH) are now set to lead a study of mRNA-1273, in which healthy adult volunteers will be trialed. Nonetheless, it is still expected to be 12 – 18 months before this vaccine, or any other, is made widely available due to the longevity of clinical trials. It is imperative that the vaccine is both effective and safe.
Q. If there are multiple strains of the virus, is developing a vaccine futile?
A. When we think of diseases such as the flu, we know that there are multiple strains and that vaccines only protect against the strains for which they have been developed. Fortunately, the structure of COVID-19 is easier to target than that of the flu, as its genetic material is all encoded on a single RNA molecule (whilst influenza consists of 8 segments). Though research is consistently being done on ways to make vaccines more effective at combating multiple strains (i.e. by focusing the immune response on a more stable target than changeable antigens), the truth is that the immediate goal must simply be to develop a COVID-19 vaccine that works.
Q. Why are antivirals being spoken about alongside vaccines?
A. Antivirals can be used as a treatment for those already suffering from COVID-19, whilst vaccines act more as a control measure, and will seek to immunize people in advance of them contracting the virus.
Generally, scientists are investigating the re-purposing of existing drugs (e.g. chloroquine for malaria and various drugs for Ebola, HIV and TB). The advantage of any existing drug being effective is that the critical but lengthy regulatory processes needed to ensure such drugs are safe could be fast-tracked, so treatments could be rapidly rolled out without extensive safety testing.
Feature image is original artwork by PhD candidate Chiara Crestani, ©2020.