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Thursday, March 16, 2023

Science Based Medicine and Masking

As some readers may know, I have been involved for many years in exposing flawed research and unfounded claims for the treatment of chronic fatigue syndrome/myalgic encephalomyelitis (ME/CFS), and more recently long Covid. This has led me to Science Based Medicine, an invaluable website that is "dedicated to evaluating medical treatments and products of interest to the public in a scientific light, and promoting the highest standards and traditions of science in health care." As explained on the website,

Online information about alternative medicine is overwhelmingly credulous and uncritical, and even mainstream media and some medical schools have bought into the hype and failed to ask the hard questions.

We provide a much needed “alternative” perspective — the scientific perspective.

Good science is the best and only way to determine which treatments and products are truly safe and effective. That idea is already formalized in a movement known as evidence-based medicine (EBM). EBM is a vital and positive influence on the practice of medicine, but it has limitations and problems in practice: it often overemphasizes the value of evidence from clinical trials alone, with some unintended consequences, such as taxpayer dollars spent on “more research” of questionable value. The idea of SBM is not to compete with EBM, but a call to enhance it with a broader view: to answer the question “what works?” we must give more importance to our cumulative scientific knowledge from all relevant disciplines.

SBM does not only critique so-called complimentary and alternative medicine (CAM), however. The site also addresses mainstream studies that are underpowered or misleading, which gets me to the point of this post. Much has been made, especially in the right-wing media, of a recent Cochrane report has been said to conclude that masking is ineffective against Covid. In fact, that was not the conclusion of the study, nor could it have been given the flaws in methodology, despite frequent talking points to the contrary.

SBM has had two extremely informative posts on the Cochrane report, which I will excerpt below.

First, from Steven Novella, a founder of SBM and a clinical neurologist at Yale:

Let’s take a look at the recent Cochrane review. This is a review only of controlled studies – the kind of study that is most likely to underestimate the effect of mask-wearing. They did not included other kinds of studies. Not all of the studies reviewed were of COVID – they included studies of other respiratory viruses (which therefore may be different) and they included studies that were not taking place in the middle of a pandemic. This is a huge red flag, as it is pretty clear from existing data that masks only work in high-risk situations.

The one study they included of health professionals in a high risk setting only compared surgical masks with N95 masks, which showed no statistical difference, but did not compare either to no mask. Also, health care professionals are the most likely to engage in the full range of protective behavior (distancing, hand washing, protective face shields, gloves and gowns). Given this, it is not surprise that the difference between a surgical mask and an N95 mask was not statistically significant.

But the biggest error I see in reporting this study is the conclusion that it shows that “mask mandates don’t work”, when that was not even studied. Studies looking specifically at mask mandates show that they do work.

Second, from David Gorski, a surgical oncologist at Wayne State:

I want to ask: What is it about Cochrane and EBM fundamentalists who promote the EBM paradigm as the be-all and end-all of medical evidence, even for questions for which it is ill-suited, that can produce misleading results?

Cochrane meta-analyses are notoriously tricky to do. First of all, you have to decide what the question is. Then you have to decide what studies out there address the question. Then, for the case of something like masks, you have to realize that you will, by the time you go through the literature and apply EBM standards to them, looking the highest quality RCTs, you will be looking at only a small, highly select part of the literature. While this is fine for new drugs and asking if they are efficacious, for a multifactorial question like whether masks slow the spread of COVID-19 at the population level, a large amount of compelling and high quality scientific evidence could well be excluded because the EBM paradigm demands it.

Yet, as I like to point out, no EBM adherent seriously doubts that smoking and tobacco can cause lung cancer, heart disease, and a host of other maladies, even though there is not and never will be an RCT testing whether smoking causes these conditions because such a study would be profoundly unethical.

There is much more to the Novella/Gorski critiques of the Cochrane report, including information about the lead author, who is a frequent confrere of anti-vaxxers.

But this is already a long post, so let me just suggest that it would be highly informative to check Science Based Medicine daily. There is almost always something interesting.

Posted by Steve Lubet on March 16, 2023 at 08:00 AM | Permalink


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