THE TRUTH ABOUT MASKS

Doctors tending to black-plague patients in 17th-century Europe felt vulnerable. They believed the disease was spread by bad air known as “miasma”, making every breath risky. So they wore beaks containing dried herbs, spices and flowers thought to purify air inhaled through holes at the beak’s tip.

For centuries, miasma was also blamed when people in warm climates were sickened or died after breathing swamp air. The actual culprit, of course, was the malaria (mal-air) parasite transmitted by mosquitoes. Plague was eventually revealed to be due to a bacterium spread by flea bites, contaminated tissue or fluid, and sneezes or coughs from infected lungs.

Unlike miasma believers of the past, we know that germs exist. We need to understand their strategies for spreading between victims if we are to devise counter measures to prevent ourselves become infected. The virus that causes Covid-19 spreads chiefly via a strategy that’s virtually airborne pestilence: minuscule virus-laden particles borne on exhaled breath.

This summer, the virus will