Great news! Face masks protect you from COVID (?)

“Mask-wearing cuts Covid incidence by 53%, says global study,” proclaims The Guardian, followed by several other sites all rushing to broadcast the exciting news.

A stunning headline, but one that seems somewhat anachronistic – after all, don’t we have vaccines now? Have not face masks become relics of the past, something that belong to grim medieval days when the only things people could do to prevent contagion were cover up their faces, keep away from others as far as possible, and hope for the best?

The article does actually give a passing mention to vaccines, noting that they “are safe and effective and sav[e] lives around the world. But,” the author continues, “most do not confer 100% protection … and it is not yet known if jabs will prevent future transmission of emerging coronavirus variants.”

In fact, if you read carefully, it is obvious that they don’t prevent transmission of current variants either, given that “the virus is still infecting 50 million people worldwide … due to the highly transmissible Delta variant.” Was that a factor in motivating researchers to conduct a “systematic review and meta-analysis of non-pharmaceutical interventions.” Perhaps. In any case, guess what? The review concluded that “mask wearing, social distancing, and handwashing are all effective measures at curbing cases.”

The source? The BMJ. We’ll get to them a little bit later.

The article continues by describing how such “non-pharmaceutical interventions … are known to be beneficial in fighting respiratory infections like flu…” which is interesting, considering that probably no one reading either this article, or the one in The Guardian, has ever encountered a person wearing a face mask in order to protect himself or others against influenza. Not to mention the fact that numerous studies dating back to BCE (before the coronavirus era) have concluded that face masks do not confer reliable protection against the vast majority of airborne infections.

Apparently, “until now, reviews have not been robust enough to allow experts to make firm conclusions about the effectiveness of such measures.” That is to say, presumably, that the several large-scale studies that have been done either did not produce the desired results, or their methodology was somehow found deficient.

In any case, after this intriguing introduction to an allegedly first-ever-of-its-kind meta-analysis, let’s look at the article’s description of the research.

“Results from more than 30 studies from around the world were analyzed in detail, showing a statistically significant 53% reduction in the incidence of Covid with mask-wearing and a 25% reduction with physical distancing.”

Passing the 50% mark is actually significant for another reason – the FDA has determined that it will only consider an intervention against COVID to be effective if it can show above-50% effectiveness. (The Guardian did not go the extra mile and conclude that social distancing is therefore a waste of time and aggravation.)

At this point, we will just note that meta-analysis was deemed “not possible for other measures, including quarantine and isolation, universal lockdowns… [etc.] due to differences in study design, outcome measures and quality.” We’ll come back to this later, too.

There ends The Guardian’s article, save for a quick round-up of what European countries are doing about masks and tut-tutting about their lax attitude given the state of things and so forth.

The Guardian didn’t see fit to produce any of the meta-analysis for closer perusal, so we did. Let’s take a look:

“72 studies met the inclusion criteria, of which 35 evaluated individual public health measures and 37 assessed multiple public health measures as a ‘package of interventions.’” So, 37 studies were knocked out right from the start; in fact, it’s a little more complicated than that, as “650 studies were [originally] eligible for full text review”; for various reasons, only 72 met the inclusion criteria.

However, although The Guardian cites “results from more than 30 studies,” the BMJ makes it quite clear that only “eight of 35 studies were included in the meta-analysis.” Of those eight, just “six studies with a total of 2627 people with Covid-19 and 389 228 participants were included in the analysis” of face mask efficacy. Furthermore, “heterogeneity between studies was substantial … [and] risk of bias across the six studies ranged from moderate to serious or critical.”

At this point, scroll back up a few paragraphs to where it was noted that meta-analysis of other interventions was ruled out in advance due to issues with (among other things) “quality.” For some reason, six studies with bias ranging from moderate to critical were not ruled out due to quality concerns.

Possibly it was with things like that in mind that the BMJ concluded in a relatively subdued tone that “a benefit” could be associated with mask wearing. But its statement that “non-pharmaceutical interventions have been shown to be beneficial in fighting respiratory infections” including those transmitted by “aerosols” is interesting, and it’s worth checking out the source they provide – the World Health Organization, in a study from its Global Influenza Programme from 2019.

According to the review described there, “ten relevant RCTs were identified … to quantify the efficacy of community-based use of face masks, including more than 6000 participants in total.”

“In the pooled analysis,” it continues, “the evidence was insufficient to exclude chance as an explanation for the reduced risk of transmission … there was no evidence that face masks are effective in reducing transmission of laboratory-confirmed influenza.” In fact, it found that there was “moderate quality of evidence involving >6000 participants that face masks are ineffective in reducing influenza transmission in the community.” Bizarrely, the “recommendation” was therefore that “Face masks worn by asymptomatic people are conditionally recommended in severe epidemics or pandemics, to reduce transmission in the community. Disposable, surgical masks are recommended to be worn at all times by symptomatic individuals when in contact with other individuals. Although there is no evidence that this is effective in reducing transmission, there is mechanistic plausibility for the potential effectiveness of this measure.” (Emphasis added.)

In other words… well, draw your own conclusions.

The review also noted that “face masks are not appropriate under some circumstances (eg. during sleep).” I just included that for a laugh; don’t worry.

The authors also commented that compliance with wearing medical face masks was often below-par, because “multiple masks per day” were required in order to be even remotely effective. They added that, “reusable cloth face masks are not recommended,” which was another point of interest, given that “new research from the University of Colorado Boulder” found that “cotton cloth masks filtered out up to 23% of the [allegedly] smallest particle size (0.3 microns) on which the [corona]virus can travel.” 23% may not be much, but it’s not nothing, and given that their findings showed that surgical masks filtered out anything “between 42-88% of the tiny particles,” perhaps cotton masks aren’t so useless after all (in comparison, at least)?

Ah, but wait. The researchers were “assuming that there are no gaps between the mask material and the person’s face … Previous studies have reported a drop of over 50% in filtration efficiency … in the presence of minor leaks when compared with a perfect seal condition.”

Previous studies – lots of them – have also found that the proportion of people wearing masks “properly” is quite small; that most people don’t chuck out old surgical masks regularly but wear them for long hours; and that when removing them or touching them, the likelihood of transmitting anything on the mask to wherever careless fingers touch is quite high.

The results of one study even strongly suggested that if it’s transmission of disease people are worried about, it might be better not to wear a mask.

At the end of the day, one fact bears noting: “Face mask market to surpass $21.2 billion by 2026.”