My apologies, I missed that link.
So you're going to reference the Bangladesh study. OK. Interesting choice since the Bangladesh study is included in the Cochrane Review you seem eager to dismiss/downplay. It's also interesting to note that this was really the ONLY attempt at a large randomized controlled trial of masking at any point during the pandemic, which is odd since it's such a hot-button issue.
Let's see what the Bangladesh study actually found. Here is the link again, for easy reference.
The proportion of individuals with COVID-19–like symptoms was 7.63% (N = 12,784) in the intervention arm and 8.60% (N = 13,287) in the control arm, an estimated 11.6% reduction after controlling for baseline covariates.
OK. So here we see an ~11% reduction in cases. It's worth noting that this is a far cry from the outlandish estimates that the CDC promotes. Let's take a look at this gem, published by the persistently, eminently flawed MMWR.
View attachment 328592
Wow! The CDC claims that wearing a CLOTH MASK (homemade from your old Guns 'N Roses T-shirts) reduces your infection odds by a WHOPPING 56%! If you choose a surgical mask, it's 66%! So then why did the only large, randomized controlled trial show a much smaller 11% reduction in infections in people wearing surgical masks? Seems a teensy bit disparate, wouldn't you say?
There are also some considerable problems with the Bangladesh study that call into question its results (emphasis added).
In this commentary, we re-analyze this trial using simple non-parametric tests. Upon reanalysis, we find a large, statistically significant imbalance in the size of the treatment and control arms evincing substantial post-randomization ascertainment bias by unblinded staff. The observed decrease in the primary outcome is the same magnitude as the population imbalance but fails significance by the same tests (see Fig. 1 and Table 1). This reanalysis thus complicates drawing any causal link between masks and the observed decrease in population-rate of symptomatic seropositivity.
Although raw numbers were not presented in the published paper, the primary outcome differed by a total of just 20 cases between the treatment and control arms: In a study population of over 300,000 individuals, there were 1106 symptomatic seropositives in control and 1086 in treatment.
...
Nonetheless, the data is consistent with mask wearing having modest or no direct effect on COVID-related outcomes in this experimental setting.
A recent randomized trial evaluated the impact of mask promotion on COVID-19-related outcomes. We find that staff behavior in both unblinded and supposedly blinded steps caused large and statistically significant imbalances in population sizes. These denominator differences constitute the rate...
trialsjournal.biomedcentral.com
So the Bangladesh RCT originally found a risk reduction of around 11.6% in the mask-wearing group (which is a far cry from what the CDC tells us masks are capable of),
but there were issues with the trial that call into question its results on causality.