It’s not like they just decided - they did, they actually just decided. The change in cloth mask guidance proves it: no new data, we always knew they were ineffective.
Cloth masks are estimated to be in the 50-60% effectiveness range. To me, that's quite effective, not ineffective. Especially when applied across an entire population.
I think you're off by an order of magnitude (5-6%) if you're referring to the risk of infection vs not wearing a basic, correctly worn surgical mask. And this is pre-omicron; omicron is far more transmissible.
You're both right - by the time Omnicron rolled around it was evident that cloth masks were not as effective at preventing transmission.
That said, cloth masks were always recommended for gen pop given the low availability of N95 surgical masks. They're still better than nothing, and we're still learning more about this disease so it's subject to change even further as more observations are made.
No. Cloth masks are understudied and probably don’t do much. What does do a lot, probably, is a dynamic where millions of people wearing ineffective masks thinking they are effective, and making bad choices entirely due to that bad assumption, like not wearing an N95, closing distance with people, or going indoors when it could have been avoided.
N95s and similar are obviously better but cloth masks do ok. Also remember they changed guidance to recommend cloth+surgical masks, which everyone laughed at. Lo and behold that combination tests in the 80% filtration range.
So cloth masks work, the guidance for double masking was valid, and the N95 recommendations more valid still.
I didn't laugh at the double masking guidance, I just laugh at the false equivalencies made across the CDC's guidance that refers to "masks" as though there's not a universe of difference between a re-used, sporadically worn, bacteria filled cloth mask and a clean, properly fit, N95. Total fail.
Well there's new data it's just not health related.
"In fact, support for mask mandates has reached its lowest level since we began asking in August 2021. Now, a narrow majority (51%) support their state or local government requiring masks in public places compared to the roughly 63% that had over the last 6 months."
There is literally new data every day. Case counts change, hospital usage changes, etc. The change in mask guidance is also not universal - it is dependent on that exact data. The CDC maintains a county-by-county map of the data so you know exactly what the guidance is each day based on the latest data.
There was no new data to support a change in guidance on cloth masks. The argument made is that omicron was the factor which warranted the updated guidance on cloth masks. There is no data to support the idea that cloth masks were suddenly uniquely unsuited as countermeasures.
Edit: The CDC is so infuriating. They still link the term “masks” to this page, that shows a picture of some useless facial decorations on the same page discussing N95 respirators. If we had a sane CDC, all imagery and messaging would be around N95s. They have killed thousands of people with the implicit lie strewn across all their messaging that there some kind of meaningful equivalency to be made between all masks. The unqualified term “mask” should have been struck from the messaging two years ago. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si...