Q. Does wearing surgical masks reduce the spread of illnesses?
A. Sometimes. “Several studies have shown that masks can reduce the amount of infectious particles shed into the air while coughing, talking and breathing when someone has an infection of the respiratory tract,” said David P. Calfee, chief hospital epidemiologist at NewYork-Presbyterian/Weill Cornell Medical Center.
But he called masks only one component of respiratory hygiene, which also includes covering the mouth and nose when coughing or sneezing; frequent hand-washing; and keeping three feet away from others when possible.
While the evidence does suggest that a mask may protect others from the wearer, can a mask protect the wearer? Dr. Calfee says it depends on what you are trying to protect yourself against.
Masks prevent larger respiratory droplets from reaching the mucous membranes, and so have long been used by people caring for patients with infectious diseases transmitted by large droplets, including influenza and whooping cough. But the smaller airborne particles associated with certain diseases, like tuberculosis and measles, can pass through or around masks.
A few studies have shown lower infection rates among household contacts of people with respiratory virus infections when using masks, Dr. Calfee said. But some studies found that most people could not wear a mask for long periods. So even if it is proved effective, a mask may not be very practical.
