Why a new COVID-19 diagnostic test is urgently needed 

Published on April 29, 2020

By Professor Geoff Pilkington 

We are in the midst of a major pandemic with COVID-19. Such major outbreaks seem to occur about every 200 years, although in recent years we have experienced a number of epidemics based largely around mutation of viruses.   

According to the World Health Organisation, infectious diseases are largely under control due to vaccine programmes. However, this current outbreak relates to a novel pathogen, SARS-CoV-2. This is an aggressive form of coronavirus, a group of viruses which have been recognised for some time now.  

SARS-CoV-2, like avian flu, swine flu and others before it, is a zoonosis – a pathogen which passes from species to species causing disease in the human host. With this new pandemic, the policy of self-isolation and social distancing is wise and should be practiced with vigilance.  

To resolve the current situation however, we urgently need to develop: 

1. an antigen assay (a test) in order to establish who has contracted the virus 
2. an assay to establish whether individuals who have contracted the virus (and are either symptomatic or asymptomatic) have developed immunity to the virus 
3. an effective vaccine to protect against the disease. 

There are three problems associated with this 3–step process. 

1. The antigen assays (tests) which have been purchased and assessed by government have been found wanting. These tests are unreliable and qualitative rather than quantitative. This means they do not assess the viral load (the amount of the virus within individual patients), and neither do they assess active virus (whether or not someone is infectious).
2. The antibody assays also need to be quantitative. They should determine whether recovered patients have partial or total immunity. With partial immunity only, patients may be subject to contracting the disease a second time. 
3. A new vaccine must be both effective and safe. The various pre-clinical tests in vaccine development are currently time consuming and most involve animal testing. If such testing were replaced by new approach methodologies, including sophisticated human 3D in vitro models, there would be significant benefits.  Firstly, it could drastically reduce the time to develop and deploy a much-needed vaccine.  And secondly, the tests would be more representative of the human patient. The prime consideration, however, is that the vaccine is deemed to be safe for the various sectors of recipients (based upon age, prior medical history etc). 

It goes without saying that an effective vaccine should be developed as rapidly as possible in order to protect vulnerable individuals, including the elderly, those with pre-existing medical conditions which compromise their immune systems and, of course, the front line staff who care for patients during the course of their illness.   

Increased speed to clinic is also particularly significant for some of the agents which are currently being assessed as potential candidates with which to treat COVID-19 patients, such as repurposed drugs. 

Professor Lorna Harries’ COVID-19 research addresses the first of these stages in developing a quantitative test of active virus in terms of viral load. Her research will have a knock-on effect in prioritising patients and making important clinical decisions. It will also lead to informed practice in employment of staff, exposure of the public and the utilisation of steps 2 and 3 above. 

The project uses existing methodology which has been modified to answer the specific questions required during the pandemic. It has two phases: the initial laboratory work-up, and the evaluation of results. The team at the University of Exeter is multi-disciplinary, engaging clinical and non-clinical scientific staff with different knowledge banks and skillsets, as well as utilising data from patients. 

The impact of the project is considerable and should produce an outcome which offers a speedy addition to the armoury employed in overcoming COVID-19. 

Geoff Pilkington is Emeritus Professor, University of Portsmouth and Visiting Professor, Kings College London. He was formerly Professor of Cellular & Molecular Neuro-oncology, University of Portsmouth and Professor of Experimental Neuro-oncology, Kings College London. Geoff is Past President, British Neuro-oncology Society.

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