If you wear a mask in a British supermarket, he noted, “people react strangely,” for a number of possible reasons: the association with East Asian countries, a suspicion that you’re using something that others are more in need of, a concern that you’re wearing it because you’re ill and shouldn’t be there, a conviction that you’re “unnecessarily spreading panic.”

Still, face masks likely “played an active role in slowing down the disease transmission progress in Asian countries” relative to Western countries, Elaine Shuo Feng, a University of Oxford epidemiologist who has studied countries’ varying face-mask policies during the COVID-19 outbreak, told me. But their usage should be part of a package of containment measures, including social distancing, school closures, and possibly lockdowns to slow the spread of the coronavirus through communities.

In places such as Hong Kong, South Korea, and Taiwan, which have had relative success so far in containing COVID-19, the public and its leaders understood this reality from the start of the outbreak. As my colleague Ed Yong has cautioned, the fact that several countries that have made the most progress in containing the coronavirus also have robust mask traditions doesn’t necessarily imply causation. “China advocated mask use early on and still struggled to contain the disease,” he points out, while “Singapore reserved them for health-care workers but still flattened the curve of infections.” What can be said more definitively is that mask-wearing tends to be widespread in countries that view disease outbreaks with the gravity that comes from firsthand experience with the horror of an epidemic.

Read: We don’t have enough masks

There’s plenty of debate among experts about the risks and rewards of people wearing homemade or surgical masks in public. And in a country such as the United States, which is currently grappling with an acute shortage of masks (a reflection of the government’s failure to prepare for a pandemic by stockpiling personal protective equipment), priority for the most effective ones must go to health-care and other essential workers who are most at risk of exposure, along with those segments of the population that are most vulnerable to the virus. In such an environment, an Oprah-esque “everyone gets a mask!” policy works only as a hypothetical exercise.

Nevertheless, the general consensus among experts is that while wearing some type of mask might not do much to protect you from catching the coronavirus, it might help prevent you from infecting others if you have COVID-19. Relative to measures such as social distancing, diagnostic testing, and better equipping hospitals, public mask-wearing (even if it’s a DIY kind) is an inexpensive intervention in the midst of a pandemic—maybe not as effective as good hand-washing hygiene, but probably better than the alternative of no one covering up. And it may be especially effective when combined with other hygienic practices such as hand-washing. Plus, it has sociocultural advantages that go beyond the narrow scientific question of masks’ capacity to disrupt the transmission of the virus.