Authors' conclusions. 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.
My take: "Physical interventions to interrupt or reduce the spread of respiratory viruses" was researched because someone wanted to show the peasants just how effective masks are so no-one has any excuse for not wearing them.
Unfortunately, the researchers found no evidence that masks worked but publishing that conclusion would mean certain death in the research world so they reined it back as much as they could with no firm conclusions.
They had to do that because, prior to the pandemic, so not biased because of it, over 150 papers had already been published on the ineffectiveness and actual danger posed by masks.
Post it
Yes but ...
My take: "Physical interventions to interrupt or reduce the spread of respiratory viruses" was researched because someone wanted to show the peasants just how effective masks are so no-one has any excuse for not wearing them.
Unfortunately, the researchers found no evidence that masks worked but publishing that conclusion would mean certain death in the research world so they reined it back as much as they could with no firm conclusions.
They had to do that because, prior to the pandemic, so not biased because of it, over 150 papers had already been published on the ineffectiveness and actual danger posed by masks.