<
https://theconversation.com/yes-masks-reduce-the-risk-of-spreading-covid-despite-a-review-saying-they-dont-198992>
"The question of whether and to what extent face masks work to prevent
respiratory infections such as COVID and influenza has split the scientific
community for decades.
Although there is strong evidence face masks significantly reduce transmission
of such infections both in health-care settings and in the community, some
experts do not agree.
An updated Cochrane Review published last week is the latest to suggest face
masks don’t work in the community.
However there are problems with the review’s methodology and its underpinning
assumptions about transmission.
The Cochrane Review combined randomised controlled trials (RCTs) using
meta-analysis. RCTs test an intervention in one group and compare it with a
“control” group that doesn’t receive the intervention or receives a different
intervention. A meta-analysis pools the results of multiple studies.
This approach assumes (a) RCTs are the “best” evidence and (b) combining
results from multiple RCTs will give you an average “effect size”.
But RCTs are only the undisputed gold standard for certain
kinds of
questions. For other questions, a mix of study designs is better. And RCTs
should be combined in a meta-analysis
only if they are all addressing the
same research question in the same way.
Here are some reasons why the conclusions of this Cochrane Review are
misleading."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
