Watch: Why you should wear a face mask to fight the coronavirus

Masks don’t make you invincible, but they’re an important disease-prevention tool.

In the first crucial weeks of the coronavirus spreading in the United States, Americans were instructed to wear a face mask only if they were sick. In the absence of widespread testing, that most likely meant you’d wear a face mask if you felt the symptoms of Covid-19.

But based on what we’ve learned since then about this novel coronavirus, being symptomatic shouldn’t be the sole indicator that a person is infected. Roughly 25 percent of people with coronavirus are thought to be asymptomatic, and people who catch Covid-19 usually don’t develop symptoms until four or five days after being infected. This is one of the ways Covid-19 has been able to spread within communities, often without us knowing.

That’s why face masks are important for both sick and presumably healthy people, say public health experts Shan Soe-Lin and Robert Hecht. In early April, the US Centers for Disease control reversed their recommendations on face mask use and now advise that Americans should wear homemade cloth masks regardless of whether they are sick or symptomatic.

The inconsistency in recommendations led to a lot of confusion about whether face masks work. They do work, but they shouldn’t be thought of as a panacea in the fight against Covid-19, Soe-Lin and Hecht said. Instead, they should be employed along with social distancing and hand-washing as a three-pronged effort to stay healthy.

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