Jon Deeks Profile picture
2 Jan, 9 tweets, 4 min read
MHRA exceptional authorisation of Innova for asymptomatic individuals was issued on 22nd Dec.

This is a LIMITED approval, and the details of how and why it is LIMITED are important. It does not cover all current uses of INNOVA by Government

1/8

gov.uk/government/new…
Details here have been provided by the @MHRAgovuk by email. If any fact is incorrect here @DHSCgovuk @MHRAgovuk please let me know and I will change – it is a bit complicated and rather unusual.

2/8
First, approved test is called the “NHS Test and Trace COVID-19 Self-Test kit” - the LFT test in it is the INNOVA test.

Second, the test manufacturer is stated as “Department of Health and Social Care”, and not Innova.

This determines who has the duty of care and safety.

3/8
MHRA confirmed details of the limited approval by email (their emphasis):

“ONLY allows for the test to be used to “find” positive cases.

MHRA HAVE NOT approved the test for use in a ‘test to enable’ scenario.”

4/8
MHRA continue:

“as stated on our webpage, people should not act on a negative result and should continue to follow their local guidelines.”

“Any other use of the kit is outside of MHRA’s remit and at the manufacturer’s own risk.”

5/8
This indicates that MHRA experts have reviewed the evidence, and decided, like many others (WHO, CMO, SAGE, Royal College of Pathologists and summarised here bmj.com/content/371/bm…) that the inaccuracy in the test is too high for it to be approved as a “rule out” test.

6/8
However, @DHSCgov continues to use the test in “test to enable” scenarios – visiting in care homes, students safely travelling to and from University, school pupils remaining in class after being in exposed to a close contact, lorry drivers returning to France.

7/8
Any situation where people act because they have a negative result is a "test-to-enable" situation.

Given @MHRAgovuk has explicitly stated the test is not approved for this, the Government must now take notice (and not by tortous act/not act logic). Our health is at risk.

8/8

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More from @deeksj

21 Dec 20
What was the sensitivity and how many false positives were there from Mass Testing of University students?

Results from University of Birmingham and Universities in Scotland don’t make good reading.

SENSITIVITY 3% (not a typo)
42% of Innova positives were FALSE POSITIVES

1/15
Testing at @unibirmingham was done in our Great Hall – impressively now a testing centre. We retested a random sample of 710 Innova test negs using PCR. We haven’t heard of anybody else doing this. Preprint soon, but here are key results.

2/15

.
Our results were posted on Twitter by @alanmcn1 who organised the testing in real time, and were sent to @DHSCgovuk at the same time.

3/15
Read 19 tweets
19 Dec 20
This is a really good question. If a test has an NPV of 99% usually we would think that is great as it means if you have a negative result you have a 1% chance of having Covid. However, a 1% chance of having Covid is actually very high.
Case rates where I am at the moment are 200 per 100,000, so 0.2%. So a totally "random test" would give an NPV of 99.8%. How low should the rate be to "rule out"? Maybe 20 per 100,000? That would be an NPV of 99.98%. Clearly we are getting into decimal place madness with NPVs
Thats why I don't use them, and because they are going to vary between places and times. My preference is to talk about how much a negative result reduces the chances of Covid. Given the event is rare, the specificity is nearly 1, this is simple to get from the sensitivity.
Read 6 tweets
13 Dec 20
The John #MaddoxPrize 2020 – Standing Up For Science

During the Pandemic many scientists (including me) who were living quiet lives have found ourselves thrown into the public arena, as we know we have important and useful skills and things to say which we hope will help.
Some of this is great (such as the pride your isolated elderly Dad has starting his day by hearing you on the radio), but standing up for science generates some vitriolic nasty responses when people don’t want to hear the results.
Tomorrow @senseaboutsci @nature announce the #MaddoxPrize 2020 prize for the individual who has gone the greatest distance in Standing Up for Science in the past year – I am looking forwarding to reinvigorating my motivation from their story.
Read 5 tweets
13 Dec 20
I’ve been horrified that my tweets about Covid tests now automatically generate responses and retweets stating “PCR is a poor test” (regardless of whether I mention PCR at all).

1/13
To be a good scientist you need to keep an open mind and be open to challenging argument. But the decider are the proper scientific studies that provide evidence. None have convinced me that “PCR is a poor test”.

2/13
Stating “PCR is a poor test” challenges the evaluations where PCR is the reference standard, as well as case counts, and to some the existence of COVID entirely. If we believed it, the cases that lateral flow tests miss would be classified as being overdiagnosed by PCR.

3/13
Read 14 tweets
4 Dec 20
So the next new Covid-19 testing technology to look at is the OPTIGENE LAMP test - as covered here in the Guardian.

1/13

Experts question claimed accuracy of Covid-19 saliva tests theguardian.com/world/2020/dec…
The main body of the report is here, appendicies with data tables can be obtained by email

2/13

gov.uk/government/pub…
The study looked at using the test on RNA extracted from swabs and saliva, and directly on swabs and saliva. Key results are here:

3/13 Image
Read 13 tweets
3 Dec 20
Mass testing in Liverpool MISSED ~50% of infections and ~30% with high viral loads. Results are in this Government document, but no actual numbers or details are given.

Absolutely URGENT that @DHSCgovuk reports full data today and HALTS IMPLEMENTATION

gov.uk/government/pub…
This test is NOT FIT FOR PURPOSE for the Government's plans

It is totally unsafe to use these tests to decide somebody does not have COVID nor “infectious”.

If it were a drug surely this would warrant an immediate withdrawal from use.
Missing 30% with high viral loads is NOT SAFE. PHE studies said missed <5% - so this is more than 6 times as many.

You cannot risk people with high viral loads visiting their elderly relatives.
Read 5 tweets

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