| Without knowing how many people were wearing masks, you can’t say the much about the 10% figure. You get approximately[1] the same outcome if: (a) masks are 100% effective but only 10% wear them, and (b) masks are 10% effective and 100% wear them. Is this study showing (a) or (b)? Let us assume (b) masks only help by 10% and R0 is 2 without masks. If exponential transmission is occurring then in ~11.5 days you have the same number infected with masks as in 10 days without masks. Either way the study has ended up with a 10% figure, and that figure gets misunderstood or intentionally misrepresented. If you want to argue for the effectiveness of masks against those that don’t wish to wear them, then personally I think it is a terrible study to argue with because 10% sounds shitty. [1] Actual numbers depends on a heap of other things, but just assume those figures are right for the sake of making things easy to understand. Disclaimer: I wear a mask during Level 2 lockdown in the South Island of New Zealand, and mask wearing has no partisan meaning here AFAIK. |
I wear a mask all the time and am happy to but I agree this study, while solid in some respects, is not exactly overwhelming in making a compelling argument for masks.