Saying the effects of masking on younger age groups and with cloth masks in this study were statistically insignificant is also a misrepresentation of what the study found. The actual paper itself can be downloaded here:
We found clear evidence that surgical masks are effective in reducing symptomatic seropreva-
lence of SARS-CoV-2. While cloth masks clearly reduce symptoms, we find less clear evidence of
their impact on symptomatic SARS-CoV-2 infections, with the statistical significance depending
on whether we impute missing values for non-consenting adults. The number of cloth mask vil-
lages (100) was half that for surgical masks (200), meaning that our results tend to be less precise.
They're talking about the analysis of the sub-group that consented to blood tests for Covid antibodies through the trial, and the fact that a smaller group of people (which could also be a confounding factor) consented to these, but that if they assume the non-consenting participants had similar rates of infection as the consenting group (instead of throwing them out), that the advantage becomes more pronounced even for cloth masks.
Furthermore, they said that even without that consideration, the cloth masks still reduced symptoms of Covid, which is still a great win for masks, as it seems they reduce the viral load received by an individual enough to reduce the severity of their infection. So saying the overall advantage of masks was statistically insignificant isn't really true.
What the trial really found was indeed that masks seem to work, and surgical masks work better than cloth masks. This aligns with what many other studies have found as well. However, even though that's probably a valid inference to draw from the data collected in the trial, it's not really what the trial was designed to find, which was more specifically that if you actively distribute masks to people and encourage them to be worn, then more people will indeed wear them, and this in turn seems to have a positive effect on reducing both the transmission and severity of Covid.
The question is how effective masks are w.r.t. Covid. For this the test really needs to be seroprevalence, not just symptoms. Symptoms can be caused by many non-Covid causes like allergies or the common cold.
The researchers state:
> We selected the WHO case definition of COVID-19
for its sensitivity, though its limited specificity may imply that the impact of masks on symptoms comes partly from non-SARS-CoV-2 respiratory infections
https://www.poverty-action.org/publication/impact-community-...
From the paper:
They're talking about the analysis of the sub-group that consented to blood tests for Covid antibodies through the trial, and the fact that a smaller group of people (which could also be a confounding factor) consented to these, but that if they assume the non-consenting participants had similar rates of infection as the consenting group (instead of throwing them out), that the advantage becomes more pronounced even for cloth masks.Furthermore, they said that even without that consideration, the cloth masks still reduced symptoms of Covid, which is still a great win for masks, as it seems they reduce the viral load received by an individual enough to reduce the severity of their infection. So saying the overall advantage of masks was statistically insignificant isn't really true.
What the trial really found was indeed that masks seem to work, and surgical masks work better than cloth masks. This aligns with what many other studies have found as well. However, even though that's probably a valid inference to draw from the data collected in the trial, it's not really what the trial was designed to find, which was more specifically that if you actively distribute masks to people and encourage them to be worn, then more people will indeed wear them, and this in turn seems to have a positive effect on reducing both the transmission and severity of Covid.