Do masks work?

Do face masks work against COVID19? The problem with answering that question is that the words "mask" and "work" are undefined.

"Masks" can refer to N95 masks, surgical masks, homemade cloth masks and gaiters. For protection against aerosolized virus, the N95 mask, if properly fitted, can provide some protection. The others are worthless for that purpose.

From the beginning of the pandemic, I've said that face masks can "work" for three purposes:

1. If you are infected and coughing or sneezing, they can protect others from you;

2. they can prevent you from touching your nose and mouth, two possible routes of viral infection;

3. virtue signaling, reminding people to social distance.

I see no reason to change that analysis. When the data change, I'll change my mind.

https://www.medpagetoday.com/infectiousdisease/covid19/104512?xid=nl_mostcommented_2023-05-19&mh=eb71348a5ff6ae370cc6759bc5dc3300