Face masks may help you avoid getting major illness
As health experts urge the public to wear masks to slow the spread of the coronavirus, they continue to get pushback. Among the arguments of skeptics: If masks can’t fully protect me against COVID-19, what is the point of wearing them?
Scientists’ counterargument is that masks can help reduce the severity of the disease caused by coronavirus even if you get infected.
There’s now mounting evidence that silent spreaders are responsible for the majority of transmission of the coronavirus — making universal masking essential to slow the spread of the highly contagious virus, experts say.
Q: What’s the point of wearing a cloth face covering if it doesn’t filter out everything?
A: Cloth face masks still provide a major protective benefit: They filter out a majority of viral particles.
As it turns out, that’s pretty important. Breathing in a small amount of virus may lead to no disease or a more mild infection. But inhaling a huge volume of virus particles can result in serious disease or death.
That’s the argument Dr. Monica Gandhi, professor of medicine at the University of California, San Francisco and medical director of the HIV Clinic at Zuckerberg San Francisco General Hospital, is making about why — if you do become infected with the virus — masking can still protect you from more severe disease.
“There is this theory that facial masking reduces the (amount of virus you get exposed to) and disease severity,” said Gandhi, who is also director for the Center for AIDS Research at UC San Francisco.
Q: What evidence supports this theory?
A: The idea that a lower dose of virus means less severe illness is a well-worn idea in medicine.
Even going back to 1938, there was a study showing that by giving mice a higher dose of a deadly virus, the mice were more likely to get severe disease and die, Gandhi said.
The same principle applies to humans. A study published in 2015 gave healthy volunteers varying doses of a flu virus; those who got higher doses got sicker, with more coughing and shortness of breath, Gandhi said.
Q: What happens if a city dramatically masks up in public?
A: If Gandhi is right, it may mean that even if there’s a rise in coronavirus infections in a city, the masks may limit the dose of virus people are getting and result in less severe symptoms of illness.
She cited an outbreak at a seafood plant in Oregon where employees were given masks, and 95 percent of those who were infected were asymptomatic.
Gandhi also cited the experience of those aboard a cruise ship traveling from Argentina to Antarctica in March, as documented in a recent study. Passengers got surgical masks; the crew got N95 masks. But instead of about 40 percent of those infected being asymptomatic — which is what would be expected — 81 percent of those testing positive were asymptomatic, Gandhi said.