For many decades we in the health professions have had multiple studies showing that masks have next to no value with airborne organisms like viruses in non-splatter situations. This is why we in the US in modern times have not worn masks in flu season. If we can breath through the mask,  the virus - which is smaller than the breathing openings - can go right through the mask. Masks are useful to protect against wet splatter as in the dental professions where work on patients involves frequent splatter back toward the dentist and the dental hygienist. This is why the dental staff wears masks year round, but take off the masks when they stop the patient's treatment.

The key protection with viruses, that should be emphasized, is improving one's immune system or, if already at a high level, maintaining that high level. People should make a serious effort to reduce obesity, eat a nutritious diet, get proper amounts of sleep, and get regular exercise. 

Promoting masks helps to raise fear among the less medically education public raising the level of stress hormones which, in fact, decrease the immune system. So the unintended result is increasing the risk of lowering one's immunity against the viruses while the mask can't stop breathing the virus through the small openings required for breathing through the mask.

People with severely compromised immune systems can wear a mask if it may make them "feel safer" even though it is not likely to provide any practical level of protection, to compensate for the potential decrease of their own immune system from the likely rise of the stress hormones that cause the decrease in the immune system's capabilities. But for the general public of any age group, wearing a mask should be based on personal choice, after assessment of one's own level of risk.