Whether one should wear a mask us a multifaceted issue. This post will address only two of them
I’ve seen posts in which people say that masks do no good. That is wrong. They do both good and bad.
Many seem to base their claim on the fact that the holes in masks through which air passes are larger than COVID-19 molecules, i.e., molecules come through to the wearer and go out to possibly infect other people.
While that factoid is true, the area of masks is mostly material. COVID-19 molecules and saliva teeming with COVID-19 get caught on the inside and outside of the mask. So, masks stop some of an infected person’s shedding of COVID-19 molecules (and wearing a mask does not prevent COVID-19 molecules from getting to the wearer).
On the other hand, “viral load” is a very big deal. Each COVID-19 molecule that enters a body starts multiplying. As soon as a well functioning immune system detects the presence of the virus, it starts fighting the virus, including producing antibodies against the intruder. Each antibody can kill only one COVID-19 molecule. How ill a person becomes very much depends on whether the pace of the body’s antibody production exceeds the pace at which the virus is reproducing.
A person’s immune system is much more likely to outpace the virus if the “load” that enters a person’s body is a single COVID-19 molecule (as opposed to say, a person at the peak of their viral infection coughs in the face of the person at the same moment they happen to be taking in a deep breath. An immune system trying to outpace many thousands of multiplying COVID-19 molecules is less likely to catch up before it is too late.
The flip side is that one of the body’s ways of fighting the virus is to eject them by coughing. If the virus gets caught in a wearer’s mask, some of the molecules will go right back to where they came from each time the mask wearer breaths in. Once back in the body, those recycled molecules will continue to replicate.