John Bye Profile picture
1 Dec, 8 tweets, 3 min read
The government has now released some info on how LFTs compared to PCR in field tests in Liverpool. h/t @ScienceShared

It's not great.

LFTs found about half the people that tested positive with PCR. Which is a little better than my back of the envelope estimate.

But... Image
It only found "more than" 70% of people "with higher viral loads, who are likely to be the most infectious".

Far less than the 95% it managed in the original Porton Down trial, which was in a lab using spiked samples, not members of the public shoving swabs up their noses.
So although the LFTs have found a few hundred cases that would have been missed otherwise, they still missed half the people with the virus that were tested.

Including 20-30% of the ones most likely to be infectious.

Source: Community testing prospectus
assets.publishing.service.gov.uk/government/upl…
Meanwhile the "prospectus", which reads like a sales pitch, claims "pilots .. in Liverpool and Merthyr Tydfil are showing positive impact".

As noted earlier, cases were already falling in Liverpool before the trial began and don't seem to be falling noticeably faster now. Image
And the "prospectus" has to admit the MHRA hasn't actually approved LFTs for community testing yet, and that they're not designed for mass testing of asymptomatic people using self-swabbing.

DHSC says it's in "ongoing and constructive dialogue" with the MHRA about this. Image
Despite all this, the government says "community testing .. may enable areas to move down through the tiers".

Dangling a possibly unrealistic carrot in front of local authorities representing the millions of people still facing the toughest restrictions as lockdown ends. Image
There's even a plan to let people in tier 3 areas go to live performances and sports events, although that at least requires TWO negative tests.

But if each test only has a 50:50 chance of detecting the virus, it's still far from foolproof. Image
All of which raises concerns about how and why the tests are being fast tracked before the full data from Liverpool has been published.

And whether the tests are sensitive enough when used this way to avoid giving people a false sense of security.

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with John Bye

John Bye Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @_johnbye

4 Dec
This week's Test & Trace report shows cases falling sharply in the week to November 25th, thanks to lockdown 2.0.

There's also a sudden big improvement in contact tracing performance (which turns out to be smoke and mirrors), and some odd revisions to old pillar 1 testing data. Image
Cases in England were falling sharply towards the end of November, with both the number and percentage of people testing positive falling by about a quarter compared to the previous week.

There's a small drop in the number of tests done, but it may well be due to reduced demand. ImageImageImageImage
In case there's any doubt about the effectiveness of lockdowns, regional data shows clearly that all areas where cases were level or still rising when lockdown 2.0 began started falling in perfect unison about a week later.

The question now is whether that can be sustained. Image
Read 15 tweets
2 Dec
This week's ONS weekly deaths report again shows deaths well above normal in the week to November 20th.

All causes deaths were 21% above the five year average, meaning 2,169 extra deaths.

And still well outside the normal range (showing by the dotted lines on the graph below). Image
Excess deaths are also still tracking the same curve as all measures of covid-19 deaths. Image
And as usual, most death certificates mentioning covid-19 listed it as the underlying cause of death (ie, they died "from" it not "with" it).

87.5% in the latest week. Image
Read 5 tweets
24 Nov
The latest ONS report shows another rise in excess deaths in the week to November 13th.

All causes deaths were 18% above the five year average, meaning 1,917 extra deaths.

Still far above the highest number of deaths we've seen in any of the last five years.
And excess deaths are still following almost exactly the same curve as all measures of covid-19 deaths (due to, involving, and within 28 days of a test).

This is not a coincidence.
As usual, the vast majority of death certificates in that week which mentioned covid-19 had it listed as the underlying cause of death - 88%.

In other words, people are mostly dying "from" covid-19, not "with" it.
Read 7 tweets
23 Nov
Shocking scenes at Randox's lab in last week's @C4Dispatches report.

Staff crammed together on 12 hour shifts, huge stacks of boxes waiting to be unpacked, delays processing tests, samples accidentally thrown away, faulty tubes leaking, sealed tubes jumbled together in boxes...
It's no surprise Randox seems to have one of the worst void rates in the Lighthouse Lab network.

Especially after previous scandals at the company, and cases where covid tests had to be binned or shipped overseas when they couldn't keep up.

google.com/amp/s/amp.belf…
And yet despite these failings there don't seem to be significant numbers of false positives.

The same lab handles tests from Premiership Rugby. In late August / early September, when they were running over capacity, their positivity rate was under 0.1%.

Read 5 tweets
22 Nov
The @DailyMailUK and @RossjournoClark have published another article downplaying the second wave, which got a government health warning from @DHSCgovuk, who said it was "misleading".

That's putting it mildly.

Here are a few of the issues I spotted...
1) They claim half of all hospitals don't have any covid-19 patients.

That's because they counted mental health units, cosmetic surgeries, community health centres and specialist units like Moorfields Eye Hospital. These would NEVER treat covid patients.

2) They claim 1,293 less hospital beds are occupied than last November.

But they're comparing one day (November 5th) in 2020 to the average for a whole quarter (October to December) in 2019!

NOT the November average, as they say.

This clearly isn't a useful comparison.
Read 14 tweets
20 Nov
So where we are is:

1) Priti Patel claims she didn't know that shouting and swearing at people working for you is bad.

2) Boris Johnson is fine with this kind of behaviour from his ministers.

3) His adviser on ministerial standards isn't, and has promptly resigned.
Lest we forget, Patel is no stranger to breaching ministerial standards, after she was caught having secret meetings with the Israeli government while supposedly on holiday, and was forced to resign from her job as International Development Secretary.

bbc.co.uk/news/amp/uk-po…
And now the senior civil servant whose departure from the Home Office sparked the investigation has weighed in, saying that, contrary to Patel's claims that she didn't know she was upsetting people, he'd talked to her repeatedly about her behaviour.

Read 5 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!