No, this study did not say masks don’t work

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Confusion of the two sentences is such that the Cochrane Group, which Published on January 30 study Which caused a lot of talk, and he saw fit After clarifying March 10:

Several commenters have claimed that a recently updated Cochrane review would show that ‘masks don’t work’, an interpretation that is both inaccurate and misleading. »

The publication in question is a review of the scientific literature. The Cochrane (formerly known as ‘The Cochrane Collaboration’) is a British non-profit organisation. which was formed Specifically for the purpose of publishing abstracts of the scientific literature. This January 30 post is dedicated to the effectiveness of “physical interventions” (not just masks) in reducing the incidence of “respiratory viruses” (most studies were conducted during flu seasons, including many during flu season). 2009 H1N1 pandemic). was the sixth from series Dedicated to this topic since 2006.

This time the authors analyzed 78 studies published over the past two decades. Not surprisingly, one conclusion is that it is very difficult to distinguish the effectiveness of a mask from the effectiveness of other health measures, especially when applied simultaneously.

As Cochrane Library Editor Carla Soares Weiser explained in its March 10 update: Due to the limited evidence provided, “Review is unable to comment on a question.”

Measurements limits on the mask

What borders are we talking about? For one thing, out of the 78 studies, only 10 focus primarily on what happens when people wear a mask versus when they don’t. Five others compared the effectiveness of different types of masks, particularly among healthcare workers.

At most, we can point out that of the 10 studies that focused primarily on masks, the two that were conducted during the COVID-19 pandemic concluded that they were effective.

On the other hand, even when comparing mask-wearing groups to non-mask-wearing groups, it is very difficult, if not impossible, to tell whether they wear them all the time or whether they wear them appropriately.

For example, one of the studies, published in 2012, focused on students living in residence halls; Some of them have been required to wear masks for at least six hours a day while in residences. The study was conducted during the flu season. The researchers did not find a “significant” difference in the infection rate, but they did note that the students were also going to class or to social events, without necessarily wearing a mask.

A broader note of the other nine studies mainly related to mask wearing, site Health Comments Observed on February 1 Giving masks to people does not guarantee that they will be worn. “Most studies do not measure compliance with mask wearing.”

In short, the most that can be said is that the Cochrane review looked at the effectiveness of efforts to encourage mask-wearing, but without checking whether those efforts made a difference.

One cited study, conducted during the pandemic, took this extra step: Made in Bangladesh, consisted of distributing masks in several remote villages, giving the information to local leaders, and then comparing whether that translated into an increase in mask-wearing compared to places where there was no room for such distribution. Mask wearing had increased from 13 to 42% in the first villages, and the researchers noted a decrease in the infection rate.

To truly assess the effectiveness of mask-wearing, more studies are needed that compare groups of people who have access to masks during a pandemic with groups who do not. But it would be morally questionable to deny a portion of the population access to a health measure.

In a quick overview of the literature, in 2021, Two American researchers confirmed The benefits to “society” will increase as more people wear masks. It should be noted that the pandemic has opened many opportunities Comparing infection rates by country or By region With periods wearing a mask was mandatory. But again, this commitment was often accompanied by other health measures, such as restrictions on movement or access to public spaces.

The same Cochrane review concluded on January 30 with a call for more large-scale studies to compare the effectiveness of these different health measures, “as well as the effect of adherence on efficiency.” Information that could be useful during the next pandemic.

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