Trish Greenhalgh Caught Out Telling More Lies on Face Masks

Trish Greenhalgh is a mask zealot who has chosen the face mask debate as the rock on which her long academic career could well perish. We expose yet another instance of her making up stories to try and prove her narrative.

Most of you reading this will have heard of Trish Greenhalgh. A colourful woman who in recent years has become known for pushing disinformation and spreading lies on national television about face masks.

Trish is the type of academic that refuses to admit when she’s wrong, even when presented with proof that she is. For Trish, her being wrong is not acceptable.

Most of the lies and disinformation that she spouts these days are about the efficacy, or lack thereof, of face masks in stopping or slowing the transmission of Covid-19.

For example, on the 20th March 2020 on the UK’s “Good Morning Britain” television show, Trish claimed that “40% of Covid cases happen by catching it from people who have no symptoms“. The topic of discussion was “Should Runners Wear Masks” and given that it was Trish herself who started the campaign to have outdoor runners masked, she was brought on as “an expert”.

Being left aghast at her claim, given that we had been staying up to date with all the latest literature on masks, we decided to email Trish for her evidence. She replied…

Asymptomatic persons seem to account for approximately 40% to 45% of SARS-CoV-2 infections

And she links to this narrative review published in the Annals of Internal Medicine.

So what is a Narrative Review?

A narrative review is the type first-year college students often learn as a general approach. Its purpose is to identify a few studies that describe a problem of interest. Narrative reviews have no predetermined research question or specified search strategy, only a topic of interest. They are not systematic and follow no specified protocol. No standards or protocols guide the review. Although the reviewers will learn about the problem, they will not arrive at a comprehensive understanding of the state of the science related to the problem.


So it’s a basic review of a subject that won’t be able to arrive at a conclusion, hence the author’s use of language such as, “seem to account”, which isn’t the type of language you’d expect to find in scientific literature.

However, that didn’t stop Trish from using the review and misrepresenting it in order to try and cover for her lies. What she did in her response to us was to reverse the author’s views, which we explain in our response to her email.

Your 40% of people are who have *caught* the virus *from* asymptomatic persons. Thus, asymptomatic transmission.

Your cited quotation is referring to 40% of infected persons *who are* asymptomatic. Thus, asymptomatic cases. 

I’m sure you’ll agree these are two quite different claims. 

Even though this was only a narrative review, many experts responded concluding that it ‘ contained a dearth of poor-quality evidence resulting in an overestimate of asymptomatic infections ‘

Trish would then respond to us with a different study that she again seems to have purposefully tried to misrepresent in order to lend cover to her disinformation on national TV.

All this has already been detailed and evidenced in a previous report and the reason I mention it here is to point out that Trish is averse to pushing disinformation on masks and when caught out doing so she refuses to apologise. In our exchange with her, after it was pointed out how she was pushing disinformation, we asked that she publicly apologise for making incorrect claims on TV. She refused and asked us not to contact her again before blocking us on Twitter. Incidentally, Trish never mentioned our interaction publicly but rather decided to keep it a secret. Wonder why that was?

Trishs’ mask disinformation

She is even so heavily invested in the facemask narrative that she advised the public against following World Health Organisation guidelines on “NOT” wearing masks when exercising.

She would fume in response;

there are also strong arguments for challenging the WHO’s advice.

Video: World Health organisation

In the above WHO video one of the reasons they give for NOT wearing masks when exercising is…

Sweat can make the mask become wet more quickly which makes it difficult to breathe and promotes the growth of microorganisms.

As fortune would have it, we found a picture of Trish out jogging and stopping for a selfie. In fact, what Trish’s selfie does is back up the advice by the WHO – advice that Trish urges the public to ignore.

Look at the part of the mask that is over the nose and mouth (red box). Note the great big brown stain? That tells us this part of the mask is wet and likely riddled with bacteria.

What’s even more bizarre is that Trish now agrees that cloth masks (like the dirty one she is wearing above) are useless against Covid.

Cloth masks are not made to any particular standard, so their properties and quality vary considerably.

In general, they are poor filters of small airborne particles.

To reiterate, Greenhalgh is all about making the evidence fit her claims on masks. When she is shown to be wrong about the evidence she presents she has no issues just straight-out lying or claiming that she had “misremembered” the data. If someone ‘misremembers’ having advised the public and this person is data and truth driven, they would offer up an apology. Trish doesn’t do that.

Her latest lie…

And if you go back to when we introduced mask mandates first, I think it was back in June or July 2020, cases were going up very, very rapidly and then the mask mandates actually brought them under control, within weeks, within a couple of weeks.

Trish Greenhalgh, BBC 5 Live Breakfast, 04/01/23

Here’s the audio of the quoted segment.

Our attention was drawn to this interview by Professor David Paton who put out a thread on Twitter debunking Greenhalgh’s claim.

We then decided to go back and look at the data ourselves on COVID cases in England during this time.

The mask mandates that Greenhalgh refers to were introduced in England on the 24th of July 2020. And by looking at the data from that time we see that she was wrong on both of her claims, which were:

  1. cases were going up very, very rapidly
  2. the mask mandates actually brought them under control, within weeks, within a couple of weeks.

Whilst the above graph is based upon 7-day rolling averages I have added below a graph showing cumulative confirmed cases of Covid.

Trish couldn’t have been any more wrong on both of her claims yet she went on in the interview to claim that it is others who are spreading disinformation around masks. Fortunately, though this interviewer wasn’t letting her off the hook and did pushback against her claims asking for proof for which Trish was unable to provide any at this time.


The Facebook-funded “fact-checking” outlet,, whom we at CJs have had to fact-check ourselves, decided to fact-check Greenhalgh and they arrived at the same conclusions as we did in this report and the same conclusions arrived at by Professor David Paton. I would always advise against solely relying upon FullFact as a reliable source, but when multiple sources reach the same conclusion and the evidence presented does the heavy lifting then one is not relying on them as a source but merely referencing them.

What did we all find? She was spreading disinformation. When FullFact challenged her on getting her claims wrong, she said she had “misremembered“. To you and me that means, ‘I lied and have been caught out.’

It does not seem right to say that infections were rising very rapidly, although there were very slight rises, within the margin of uncertainty, in the weeks when the mandates were introduced.

Nor was there a significant fall in the weeks following the introduction of the mandates, with infections remaining generally flat until September, when they began to rise at the beginning of the second wave.

Had Trish been someone interested in the truth and keeping the public record straight she would have apologised for ‘misremembering‘ and informed her followers that she’d made a mistake. But in much the same fashion as when we caught her lying (made no mention of this on social media but instead blocked us and all of our followers) she has still to post a tweet to her followers (or the greater public) on either the FullFact article or the fact she was very, very wrong in her claims.

You see when you disagree with Trish and especially if you show her to be wrong she doesn’t just block you on social media but all of your followers too. She labels anyone who disagrees with her as a troll.

Trish the face-mask zealot

Even the staunchest of Greenhalgh fans wouldn’t argue that she is very much a face-mask zealot. For her, as she said on the BBC 5 Live Breakfast show discussed in this article, masks just have to reduce spread.

But that isn’t how science works. Because you believe that something should work doesn’t mean that it does work. But what Greenhalgh does is begin from a conclusion – that masks do work – and then working in reverse order attempts to make the evidence fit and when it doesn’t she just makes things up and distorts the findings of other people’s writings to make it fit. Call her out on doing this, she will block you and your followers. Why? Because Trish can’t be wrong.

The more the evidence points to masks being of little to no help in reducing COVID-19 spread the more she doubles down in her belief that ‘masks have to work therefore we must make them work’. In the next tweet, she even calls for speaking during periods of eating or drinking to be stopped.

For Greenhalgh, it’s not that masks don’t work or can’t work but that we just aren’t wearing them enough or wearing the correct type at the right times etc. ‘They just have to work and if they aren’t working it’s our fault.’

Up next Trish posted a photo of herself on a train wearing a mask with a hose outlet that she claims is connected to a “personal rechargeable HEPA filter”. Whether this is true or not, I will leave that up to you to decide but suffice it to say that camera-happy Trish doesn’t provide a photo of this device.

When questioned on how she ensures a perfect seal around the tube, she falls silent. Not surprisingly as it’s an important question that she could not answer.

Why could she not answer it? Look at the huge gap between the mask and her face (red denotation). Even affording her claim, that she is using a HEPA device, buckets and buckets of the benefit of the doubt it’s all pretty much pointless as she’s breathing in the air from the carriage via that massive gap in her mask.

If the mask was connected to a HEPA filter and she genuinely felt that was a great idea then we must ask why she has never been pictured wearing the same odd-looking mask since. Why just this once?

What about her mask with the mouth window that she showcased once and then never again?

Why didn’t she continue to wear it if, again, she felt it was that great of an invention that she should take a selfie of herself wearing one and post it to her vetted and censored followers on Twitter?

The most plausible answer to both of the above examples is that she’s an attention-seeker and likes to see herself as an authoritative figure in the public sphere, even on subject matters that she knows little to nothing about.

The evidence points to Trish Greenhalgh being both a charlatan and a liar and shows that she doesn’t mind spreading disinformation and making up claims to suit her narrative/agenda on face masks.

My guess is that because she is very rarely challenged when appearing on corporate media outlets and as she prohibits any challenge towards her on social media, Trish has created a kind of protective echo chamber around herself wherein she is the truth and the science. When she is caught out telling lies she tries to ensure this doesn’t reach her audience and if it does and if they ask questions, she censors them.

For Trish, the debate around face masks may well be the rock on which her long academic career will perish. Indeed, to those who have been following her insane religious-like belief in masks, they will note that many academics who used to amplify her very long and closed Twitter threads (closed so as stop discussion) on masks no longer do or do so less often.

I guess when a ship is sinking, those that know the ship is sinking will try and get off.

For us, we will continue to watch the wreckage go down from a vantage point from the land of the sane and sensible.