Wonder why a pandemic spreads as wildly as it does? Wear a mask.
"People Likely to Conceal Contagious Sickness for Social Commitments"
https://neurosciencenews.com/social-behavior-contagious-sickness-25540/
"A significant number of people, including healthcare workers, conceal infectious illnesses to maintain their work and social commitments. The study, involving over 4,100 participants, found that 75% had hidden or might hide their illness in the future, often due to social plans or institutional pressures."