The thing to keep in mind is that blocking 50% of the particles does not mean a 50% reduction in infection. It may mean a 50% reduction in infection -- or it may mean a basically zero percent reduction. It depends on the exposure.
Say that in a particular covid-filled room you have a 50% chance of being infected after 5 minutes and a 99.9% chance of being infected after an hour. Under a simple model, if you wear a mask that blocks half the particles, your chance of getting coronavirus in 5 minutes would be reduced to 25%, but your chance of getting it after an hour would be 97%. So if cloth mask is your primary defense against covid, you are eventually going to get covid if you are trying to live anything close to a normal life. Blocking 50% of particles is like wearing an condom that only blocks 50% of the sperm or an umbrella that blocks only 50% of the rain.
The umbrella is a better comparison. My umbrella doesn't prevent 100% of the rain from coming in contact with me. This is good enough that the umbrella is still standard practice.
Whatever that number is, if we limit the number of particles in the air, we decrease the statistical probability that a person will come in contact to a number of particles exceeding that number.
It's a "solution to pollution is dilution" issue.
> it might actually make sense to just give everyone a very small infectious inoculum as a form of vaccination.
The biggest issue with this, as I understand, is straddling the line between causing an immune response and hurting the patient. There are live vaccine viruses, but most (all?) attenuate the virus to prevent the latter.
Or, to put it more on the nose: the half-life for an American getting CoViD under ordinary conditions seems to be longer than a year. Using your linear model, a 50% mask would make it more than two years! So half-life exhaustion doesn't seem an appropriate counterpoint.
Not true.
https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...