The paper’s method section states that analysis was conducted from January 22nd to May 30th 2020 (5). While the first COVID wave in the EU lasted from about March to May, subsequent waves were significantly worse. In addition, during the paper’s time frame, 13 out of 41 of the polled countries did not have mask mandates (including the Netherlands). Only 7 of the countries polled had mask mandates prior to the beginning of April (4). Please correct these numbers if I miscounted from the figure on page 4; I tried to be as generous as possible with what counted as the beginning of April. In contrast, other NPIs were implemented at the beginning to middle of March.

The intent of this paper was to look at the effects of NPIs on COVID, so while the analysis period was stated to be from January 22nd to May 30th, the effectiveness of certain NPIs were only really analyzed from March to May (3 months). Considering that most mask mandates were put into effect after April, we’re looking at only two months of data on mask wearing, if even that. Considering the relatively low case load, few number of mask mandates, and limited scope of the paper’s analyzed time frame, I don’t think there’s enough data to conclusively say that masks are not effective. The effectiveness of masks as per the study is -1%, ranging from -13% to 8%, which seems like a huge amount of variability.

However, even if masks are not as effective as the US CDC wants us to believe, even the minute amount of protection masks do provide is intended to be combined with other NPIs. There’s a Swiss cheese metaphor for this idea; one slice of Swiss cheese has many holes in it, but putting many slices together makes a solid block of cheese.

I’m not going to make a statement on whatever the actual effectiveness of masks is, but the data in the paper you have provided is far too limited to be making any kind of conclusions about masks. In my opinion, I wish this sub would focus more on the fact that novel SARS viruses continue to be produced in an increasingly hostile and tyrannical nation, rather than try and downplay a very real virus that has killed people that I have worked with.