COVID-19: WHAT IF WE WERE TO STOP COVID-19 TESTING?

What a stupid question!  Or is it?

There's fundamentally two types of tests:

• "Got it" tests, currently done using a technique called RT-PCR
• "Had it" tests, currently done by testing for antibodies

Two big topics.  After yesterday's shambles with Excel, let's look at why "Got it" tests for COVID-19 are done, and whether we should be doing something different.

 

BASICS OF THE VIRUS

Before we can assess "Got it" testing for the SARS-COV-2 virus (SARS2) that causes the COVID-19 disease, we need to understand some basic facts:

• The SARS2 virus is too small to be seen in the most powerful visual microscope.  An electron microscope is needed.
• The virus contains RNA, which is what allows the virus to replicate within a human cell
• There are several strains and many variations, but key aspects identify the RNA as being from SARS2
  
• When the virus is deactivated in some way, remnants of the RNA are left.  So a test for RNA does not identify whether the viruses were active at the time of taking the sample
  
• The proper way to test for active SARS2 is to grow a culture.  That takes far too long for testing purposes, in excess of 7 days
  
• People become infectious before they display symptoms. So it is important to identify presence of virus in people who are not displaying symptoms, and get them to isolate before they infect anybody more
  

 

SO WHAT OPTIONS DO WE HAVE TO TEST FOR SARS2?

There's three decreasing levels:

• Whether there is active SARS2
• Whether there is SARS2
• Whether there is SARS2 RNA

Culturing samples to identify active SARS2 is not practical, as it takes too long to culture a sample.

Could we spot intact SARS2 with some form of microscope, with AI software optimised for identifying it?  I haven't heard of such an initiative, but hopefully someone is working on it.  Wouldn't be easy to be sure it was SARS2

Which leaves us with having to 'make do' with RNA testing.  There are three major drawbacks with this approach, whatever technology is used:

• The sample has to be good enough to contain enough viruses to be detected:
• A viral infection needs some time to grow enough in the body to be detected.  This may take a couple of days after infection.  So a negative result may just be that the test was done too early
• Swabbing is notoriously unreliable, producing 30% false negatives even when done by an experienced professional.  Worse when self-swabbing
• Saliva samples are now being used, but they haven't been used hitherto because saliva contains less viruses than swabs

• As any form of RNA detects remnant RNA, a positive test result may be telling you the person has had COVID-19, but they could be no longer infectious:
• Which is why testing is not done more than a few days after initial symptoms
• If someone has been tested when asymptomatic, we don't know whether a positive result is that they have active virus, or they had the virus some time ago and are not still infectious

• Cost:
• The current RT-PCR test has been reported by the Financial Times as costing around £100 per test.  Scale that up to millions a week and the cost is eye-watering
• Alternative reliable tests are at least £20 per test.  Still eye-watering at scale
  

 

SO WHAT IS "OPERATION MOONSHOT"?

There seems to be two aspects to Operation Moonshot that are getting confused, but are both worthwhile:

• Trialling of new RNA tests:
• A test for use in hospitals, to produce results more quickly, using 'NudgeBox from an Imperial College London spinout company called DNANudge, also using RT-PCR
• A quicker, cheaper test based on RT-LAMP technology for use for the general public, using LamPORE tests from Oxford Nanopore

• Looking for a new type of test that is simple and cheap enough for everyone to use at home on a daily basis, whether symptomatic or not:
• If not as reliable as the 'proper' tests, at least be 'indicative' to identify if a proper test should be done
  

When I reviewed tests two months ago in early August, I made two key observations:

• The need for cheap indicative tests, as envisaged in Operation Moonshot.  Are people in Government reading my blogposts?
• RT-PCR was not appropriate for mass testing:
• Too complex
• Lack of availability of test reagents, although that might only have been a temporary problem
• Reliance on unreliable swabbing, as explained above
  
• Very expensive, as explained below
  

The only problem in principle with Operation Moonshot is that nothing is likely to change much this side of Christmas, nearly three months away.

SO WHY HAS RT-PCR BEEN SCALED UP?

So why has RT-PCR been scaled up, with plans to do more?

The World Health Organisation suggests that Test/Trace/Isolate is an important part of dealing with COVID-19, as does nearly every expert on infectious disease.  They are right in theory, but is that correct in practice, given what has been discussed above?

Frankly is scaling up RT-PCR more political expediency than a scientific necessity?

To answer those questions let's look at testing objectives for 'Got It' tests.

'GOT IT' TESTING

There are several objectives of 'Got it' testing:

• For patients being admitted to hospital 
• As part of overall pre-treatment testing
• To isolate those with COVID-19 away from other patients
• For general public, whether need to self-isolate or get back to work:
• Key workers, such as hospital staff
• For others
• To get contacts of positively-tested people to self-isolate, and thereby reduce transmission of the virus by people who are infectious but wouldn't otherwise know it
• Monitor level of new infections
  

There are two of these objectives that are essential, covered by NHS testing in what is called "Pillar 1":

• Hospital admissions
• Key workers, such as health workers and emergency service personnel, who need to get back to work as soon as possible
  

The other three objectives are covered by the outsourced "NHS Test and Trace", in what is called "Pillar 2":

• General public
• Contact tracing, now under threat of £1000 fine for not complying with a self-isolation instruction
  
• Monitor level of new infections

So the question posed at the start can be re-phrased as "What if we were to stop Pillar 2 COVID-19 testing"?  The answer is not necessarily obvious. 

So let's explore this question.

GETTING A PILLAR 2 TEST

There are several ways you can get a "Pillar 2" test, all of which currently involve swabbing and use of RT-PCR:

• Drive-through or temporary facility where somebody experienced takes the swab
• Take your own swab at one of these facilities, under supervision
• Take your own swab at home, with no supervision
  

The main Oxford Hospitals advise that around 30% of experienced swabs were inadequate .  There is no inherent reason why that would have improved, and self-swabbing is likely to be worse.

I had a test when the staff at the temporary facility in Oxford insisted I take a test, even though I protested I had no symptoms.  I went ahead in the interests of research. The result was negative, as expected.  But the email with that news reflected the risk of false negatives:

• I should still self-isolate for 14 days if "someone you live with tests positive or you've been traced as a contact of someone who tested positive."

• However "If you're not a contact [of someone tested positive] you may return to work if you've not had a fever for 48 hours and feel well" or otherwise get back out living 'COVID-normally'.

• At least until I show symptoms again, when I should "get tested and self-isolate for 10 days from when they start".

So it seems I would need to self-isolate for 10 or 14 days if there's any doubt.  I would also need to wait 2 days after fever or feeling unwell, which is a typical time for any other type of illness.

So that minimises the consequences of false negatives. But it means something else as well.  

There's little value getting a negative result.  Furthermore, if you have symptoms, there is little value in getting a positive result.  In practice you would have (or should have) self-isolated anyway, although it is good to know for sure.  In most cases a negative result is not going to release you from that requirement to self-isolate.  Indeed there's the prospect of a £1000 fine for breaking a self-isolation instruction.

Furthermore a positive test result only means there's RNA in your sample, not whether you are still infectious.  

In practice then, a "Got it" test is not especially helpful to the people being tested outside of a hospital setting.  

VALUE OF TESTING FOR INFECTION MONITORING

Before looking at Tracing, let's check whether there is any value in the test statistics for monitoring the location and severity of outbreaks.

Yes there is, but there are other alternative and in some respects more reliable sources:

• The Office for National Statistics "COVID-19 Infection Survey" which tests a sample of people across the country at random, for both "Got it" and "Had it", taking swab and blood samples.  The sample includes people who are not symptomatic, identifying where infections are taking place before they get reflected in the Pillar 2 figures.  The expansion of the ONS Survey to 400,000 people was announced in August.
• The ZOE app run by King's College, which involves over 4 million people who have been able to download the app, and tracking their symptoms. 
• Various other studies run by other universities

So would the loss of "Pillar 2" testing affect decisions? The recent problems with losing over 15,000 Pillar 2 test records shows the Government is not reliant on them for that purpose.  So pillar 2 results are clearly not essential for the purpose of monitoring spread of the infection, and the occurrence and size of individual outbreaks.

 

 

THE POTENTIAL VALUE OF TEST AND TRACE

 

So we've concluded that there is little added value from Pillar 2 testing in two respects:

• Little value to person being tested
• Little value to track size and location of outbreaks, because there is other reliable information available
  

The real potential value of Test and Trace is to trace contacts of positively-tested people, and ask the contacts to self-isolate.  That reduces transmission.  That's if people do it, which we know has been poor.  As has the been the poor success of the Test and Trace service managing to contact contacts.

 

Support for those being asked to self-isolate is vital, and there is the carrot of £500, but also now the threat of a £1000 fine.

Frankly I don't want to live under that shadow.  Fearing that phone call.  A risk becoming ever more likely as infection levels rise.  Having to self-isolate for 14 days with no certainty I've actually contracted the disease.

 

Indeed the only real advantage of using the new NHS COVID-19 app is to log into venues anonymously, otherwise venues are compelled to collect contact details from me.  I bet people give false details, or details of someone else. I fear being the butt of that jest. 

 

So whilst contact tracing and isolation is in theory vital in the fight against transmission, in practice it has some major downsides.  Downsides that would be justified if SARS2 was as lethal as the original SARS or MERS, but difficult to justify for SARS2, even with LongCOVID.  Even if the contact and self-isolation percentages were perfect.

BUT THE COST!

The Financial Times has reported that each test costs around £100.  Figures of around £10 billion are bandied about for the entire cost of the Test and Trace Pillar 2 process.  With the entire Health budget of around £178 billion in a normal year, the cost for the Test and Trace programme needs some serious justification.

So we have:

• Little value to person being tested
• Little value in tracking size and location of outbreaks, because there is other reliable information available 
• Ineffective and 'unwelcome' tracing service
• Extortionate cost

Looks like a no-brainer to me.  Pillar 2 testing cannot be justified, other than for the Government to show they are doing something, by complying with WHO advice.  Keeping the media off their backs, except when it goes wrong.  

Think what else we could do with that money, either to fight COVID-19 or for other initiatives. 

WHAT ABOUT CHEAPER, FASTER, MORE RELIABLE TESTING METHODS?

If false negatives could be substantially reduced, such as by saliva sampling or some other testing method, then the test results overall would be of much greater value.  If the cost was then far lower, public testing would be worthwhile.

But it would be arguably easier and more effective if Test and Trace for the general public was brought into the Pillar 1 fold, and local tracing implemented in place of the current impersonal national system.

I look forward to Operation Moonshot identifying a test that everyone could use on a daily basis, even if it was only indicative.  At least that would highlight who needs to get tested properly, and local contact tracers could follow up to extinguish a local outbreak.

 

WHAT ELSE SHOULD WE DO?

The issues with testing capacity and tracing would be substantially reduced if the new infection level would be brought down to #NearZero, alongside a whole host of other benefits:

That requires action far tougher than current suppression measures, Mass Simultaneous Self-Isolation.

Cancel Pillar 2 testing and the money saved in testing could provide full support for self-isolation and so much more. 

 

So it wasn't such a stupid question to stop Pillar 2 testing.  Pillar 2 testing should be stopped, though Pillar 1 testing should continue and be the foundation for all reliable testing in future.