Friday, March 10, 2023

Cochrane Statement On Misinterpretations Of Their Mask Study

 #17,340

Although there is ample evidence that the consistent and proper wearing of a good quality (preferably N95) face mask or respirator can dramatically reduce your risk of contracting a respiratory virus (like COVID, Flu, etc.), those who despise wearing masks - or wish to politicize them - have latched onto a Cocharne Study which they claim, proved that mask wearing was worthless. 

Exactly how people interpreted that study as a solid repudiation of face masks is difficult to answer.  The authors clearly stated:

The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions.

and 

The low to moderate certainty of evidence means our confidence in the effect estimate is limited, and that the true effect may be different from the observed estimate of the effect

But the anti-mask brigade took this as the proof they needed to declare victory.  And the internet has been riddled with echo-chamber proclamations that masks don't work ever since. 

Granted, people who wear a mask improperly, or only wear a mask some of the time, probably don't reduce their risks of getting sick very much during an epidemic.  

But I know a lot of people - including nurses who are in contact with infected individuals nearly every day - who have gone through the COVID pandemic without ever falling ill.  

The common denominator among them was they all wore their masks anytime they were in public. 

Today, following weeks of outcries from public health experts, Cochrane released the following statement, where they call their study `widely misinterpreted'. 


Statement on 'Physical interventions to interrupt or reduce the spread of respiratory viruses' review
The Cochrane Review 'Physical interventions to interrupt or reduce the spread of respiratory viruses' was published in January 2023 and has been widely misinterpreted.

Karla Soares-Weiser, Editor-in-Chief of the Cochrane Library, has responded on behalf of Cochrane:
Many commentators have claimed that a recently-updated Cochrane Review shows that 'masks don't work', which is an inaccurate and misleading interpretation.

It would be accurate to say that the review examined whether interventions to promote mask wearing help to slow the spread of respiratory viruses, and that the results were inconclusive. Given the limitations in the primary evidence, the review is not able to address the question of whether mask-wearing itself reduces people's risk of contracting or spreading respiratory viruses.

The review authors are clear on the limitations in the abstract: 'The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions.' Adherence in this context refers to the number of people who actually wore the provided masks when encouraged to do so as part of the intervention. For example, in the most heavily-weighted trial of interventions to promote community mask wearing, 42.3% of people in the intervention arm wore masks compared to 13.3% of those in the control arm.

The original Plain Language Summary for this review stated that 'We are uncertain whether wearing masks or N95/P2 respirators helps to slow the spread of respiratory viruses based on the studies we assessed.' This wording was open to misinterpretation, for which we apologize. While scientific evidence is never immune to misinterpretation, we take responsibility for not making the wording clearer from the outset. We are engaging with the review authors with the aim of updating the Plain Language Summary and abstract to make clear that the review looked at whether interventions to promote mask wearing help to slow the spread of respiratory viruses.
Read the Cochrane Review 'Physical interventions to interrupt or reduce the spread of respiratory viruses'
Friday, March 10, 2023


Sadly, far too many people will cling to their belief that masks are ineffective, and will put themselves - and others - at risk during the next epidemic or pandemic wave.