There is an abundance of evidence that masks work. Just as there is evidence that vaccines work, and anti-viral drugs work.
Right. But. ‘masks work’ can mean different things. “Do fit-tested FFP3 masks work to reduce viral exposure during one prior of contact?” is not the same thing as “do cloth masks worn in some situations reduce the overall number of cases in a population over several months?”
With vaccines and anti-viral drugs, there needs to be some evidence that it works before large clinical trials. Those trials are still needed, though, because “does it work to produce an immune response safely in one patient?” or “does it work to kill the virus in a Petri dish?” are not the same thing as “does it work in real populations in real conditions to reduce illness over a period of time?”
There are lots and lots of potential vaccines and treatments that work at the first stage of these smaller studies, but don’t work in big trials. So we decide not to use them. What we don’t do is say “yes but they worked in the Petri dish, so that means they DO work, and I will keep insisting we must use them at a population level even though we did wider trials in human patients where they failed.” That is not ‘following the science’, that is following the crazy Ivermectin fans.
Do fit-tested FFP3s work to reduce viral exposure during a limited contact? Yes they absolutely do. We test them for this, we know they work.
Do cloth masks worn in some situations reduce overall cases at population level? No, they clearly don’t. Otherwise we would have seen at least some evidence of it in case levels by now, when comparing countries that used them against countries that didn’t.
I do not know why so many people have become convinced that it is Following The Science to look at all these examples all over the world of masks not impacting population-level spread and maintain that the data is simply less important than your pre-existing beliefs, but that doesn’t seem very scientific. How far do you think the vaccine trials would have got if the results showed bugger all difference between vaccinated and unvaccinated groups, and some Pfizer exec said “ah yes BUT they do work nevertheless, look what happened in this Petri dish!”