COVID-19, A testing opportunity

The issue in tracking the spread of the SARS-CoV-2 virus throughout the population is that the two tests being suggested are, an untested antibody test, providing best results 21-28 days after showing symptoms of the COVID-19 disease, or a manpower, technology, reagent and skills intensive PCR test looking for active virus a period of time post infection.

A percentage of the population remains asymptomatic as they carry the virus but can transmit it.

The PCR tests are and will always be resource limited. Those infected with the SARS-CoV-2 virus may be infective for a period before the PCR tests will identify active infection.  The test is only accurate at the moment of time the swab was taken and there is nothing to stop someone not infected at the time of test being subsequently infected at any time after the test.  The reagents needed for the test are in a short supply across the globe and testing facilities are becoming overwhelmed.

Current “mass” screening capability used in several countries uses thermal cameras looking for people with elevated temperatures. However, it will not identify asymptomatic carriers and only detects one symptomatic indicator.

What is needed are a series of complimentary tests able to identify an infection and immune system activation as early as possible so that infected persons can isolate as early as possible to reduce cross infection risk, once isolated then individuals can be tested for specific viruses such as SAR-CoV-2 and then for antibodies.

Tests should be simple and cost effective enough to allow individuals to be tested as often as is deemed necessary. For example, healthcare staff on arrival at work and on leaving work each day.  There is currently insufficient PCR capability to do this and it is unlikely there ever will be. PCR tests are relatively expensive.

Research post the original SARS epidemic believed to have emerged in 2002 identified the utility of a viral infection marker produced by the body as part of a stimulated immune response.  The marker is called Neopterin.  There are numerous scientific papers outlining the utility of this chemical marker including:

Serum neopterin for early assessment of severity of severe acute respiratory syndrome.

The emerging utility of neopterin?

Neopterin in Diagnosis and Monitoring of Infectious Diseases

The immune system being activated and releasing Neopterin is not specific to SARS-CoV-2, however it is an early warning system that something is going on; currently there is no test that does this.

Professor Colin Self, an Emeritus professor with Newcastle University and recognised leading testing scientist as developed a simple revolutionary test that could be used for that early warning capability utilising the detection of Neopterin in saliva.

The base technology used for the test has been developed over many years of research under Framework 7 and Horizon 2020 funded research projects. It can be used to detect any small molecule where a specific antibody for that molecule can be found. It is simple positive read out test, that gives results in less than 2 minutes.

As an antibody is specific to a particular chemical structure, this methodology is extremely accurate. Professor Self has a very pure cell line producing antibodies to Neopterin. The use of saliva, the positive read out if neopterin is present and the speed of testing allows self-testing and self-reading of the result.  Each test if produced in volume batches, only costs a few pounds.

Imagine everyone being able to test themselves several times a day and if positive the more expensive PCR tests can be used in a targeted way to track SARS-CoV-2, if negative you know you do not have an immune stimulating infection.

Professor Self has told me that whilst his test is in storage as his research grants have finished, he has identified a qualified team with availability, facilities to produce a production standard test in approximately 6 weeks and then the manufacturing process to produce 10’s of thousands of test strips per day or potentially significantly more would be easily achievable.  His tests don’t need special reagents, he can grow volumes of the relevant antibodies quickly, large numbers of test strips can be manufactured easily.

A video of the test being used in real time is below:

 

The presence of small molecular weight analyte (Neopterin) gives rise to a positive line appearing out of a clear white background. Intuitively, the more line is seen the more Neopterin is present.

The cassette dipstick on the left receives neopterin-free buffer, whereas the cassette dipstick on the right receives buffer containing the small molecular weight analyte.

During the, real-time run, both cassette dipsticks display a positive control line towards the top of the window to show the devices have been used correctly. Only the cassette receiving a positive sample shows a positive test line, towards the bottom of the window.

This occurs very quickly. The fact that the positive sample is indeed positive can be seen by eye within a matter of seconds, allowing immediate action to be taken if necessary. Further development of the sticks over two minutes, allows the control line to stabilise and a quantitative determination of the concentration of the analyte.

All Professor Self needs is help taking this ground-breaking test to production. It could enable better control of pandemic conditions.