Actual mask expert Megan Mansell chimes in on the Cochrane mask review backlash
Megan Mansell is an OSHA-qualified mask expert with a background in hazardous environs PPE applications. During the pandemic years, she has addressed school boards, written articles and a book, done podcast interviews and countless twitter threads on why the strategy of masking to reduce spread of Covid won’t work.
Mansell published this technically detailed article titled, ‘Why N95s Fail to Stop the Spread,’ just a week before the publication of a new Cochrane review (30 Jan 2023) which found no evidence of benefit for masking. Mansell has already explained in great detail why this may be the case.
In case you missed it, the above-mentioned Cochrane review, titled ‘Physical interventions to interrupt or reduce the spread of acute respiratory viruses’, has reinvigorated the Great Mask Debate over the past week.
The review is an update of an earlier version published in 2020, which was too early in the pandemic to include studies on masking to prevent or reduce spread of Covid. The updated version includes six Covid-specific studies.
In the words of lead author Thomas Jefferson, “There is just no evidence that they make any difference. Full stop. My job, our job as a review team, was to look at the evidence, we have done that.” This finding applies to N95/P2 masks as well as surgical masks.
Of the physical measures assessed, the authors found modest benefits in hand hygiene. They conclude with a call for, “large, well‐designed RCTs addressing the effectiveness of many of these interventions in multiple settings and populations, as well as the impact of adherence on effectiveness, especially in those most at risk of ARIs.”
The review has been covered in detail by Eugyppius, and I recommend reading Maryanne Demasi’s interview with Jefferson, which reveals seemingly politically driven interference with the publication of the 2020 version.
Following publication of the review, the pro-mask brigade has been declaring from all available rooftops that they are having none of it. Yes, masks reduce the risk of spreading Covid, despite a review saying they don’t. That’s a real title of an article published on The Conversation yesterday. Pro- and anti-mask advocates routinely take this tack when the published science doesn’t suit them. The two sides have this and not much else in common.
However, as we’re dealing with pro-mask blowback to a nil-benefit finding from a gold standard masking review, I’ll continue with this Conversation article. The top listed author is C Raina MacIntyre, who receives funding from a mask manufacturer and is on an advisory board for another mask manufacturer. She, like her co-authors, is also a certified Expert. What none of these Experts have expertise in, though, is the safe and effective application of masks in a real-world setting.
Megan Mansell does have expertise in the safe and effective application of masks in a real-world setting, so I asked her to respond to the article by MacIntyre, et al. Mansell obliged, and her response follows. Links and references are inserted below each of Mansell’s tweets as needed.
Hierarchy of controls source link via CDC NIOSH
The Great Masking Debate is a microcosm of scientific debate throughout the entire Covid pandemic. People have dug themselves into opposing trenches, and each side rallies their Experts, like the bannermen of an army unit. The goal is to not cede ground, no matter what.
This approach is obviously anti-scientific, and politically untenable.
The press has (for their own partisan and commercial reasons) damaged public faith in the very notion of expertise, by pushing so many IYIs and conflicted Experts into the spotlight that the public is becoming thoroughly fatigued with the lot of them, and deeply suspicious. Rightly so.
The irony is that Cochrane reviews were established precisely to sift out biases of this kind. It's a sign of the times that a Cochrane review would be so flippantly dismissed. At the same time, Jefferson’s account of politically motivated interference with the publication of the 2020 iteration of the review suggests that a healthy dose of skepticism must be applied to all scientific literature, even the ‘gold standard’.
Despite our waning faith in Experts, real expertise is still a thing. An interdisciplinary approach, with input from academics in diverse fields, as well as the expertise of seasoned professionals on the ground, should assist in creating a clearer picture of what is true, and what is not.
A question for readers:
When parsing through the enormous volume of conflicting information ‘out there’, how do you decide which information to trust, and which to discard?
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The Twitter thread in which I asked for Megan Mansell’s input is still going. Mansell is quite responsive and generous with her replies, so if you have any questions for her on this topic, you can jump into the chat and ask. I suggest reading her article, ‘Why N95s Fail to Stop the Spread,’ first.