During the COVID-19 pandemic, we wore masks and kept 2 meters (6.6 feet) apart in an effort to reduce the spread of the tiny droplets we release into the air with every breath, conversation or cough. The main goal was to reduce the number of virus particles—known as virions—to which we were exposed. For each virus, a person must be exposed to a minimum infectious dose to develop disease, and in many cases, the larger the dose, the more severe the illness.
