Let's assume you have coronavirus

There are now 16 states (as of the end of June) that require people to wear face coverings when out in public. But we need to acknowledge it: many Americans really don’t want to. Our president and vice-president don’t wear masks, even though members of their staff have tested positive for COVD-19. When protestors gathered in state capitols to rally against stay-at-home orders, most did so without masks. And, as tens of thousands of Black Lives Matter activists took to the streets, many are maskless.

Mandatory masking was implemented in my state, California, two weeks ago. But as I lately strolled through several Bay Area cities, I was shocked to see how few people had face coverings. Epidemiologists are disappointed but not surprised when, just last week, California continued setting and breaking records for the highest number of daily new COVID-19 cases.

However, these new mask mandates are the right move and should be adopted nationwide. The only way we can keep COVID-19 at bay is for each of us to assume we are already infected with coronavirus—even though we feel fine—and act accordingly: Wear a mask consistently, wash hands frequently, and maintain social distance outside the house.

I grew up in Taiwan, where masks are common. When I came to the U.S., I was startled—and sometimes alarmed—to see people not wearing masks even during flu season. But remembering how I was treated when I prudently wore my surgical mask helps me understand why so many Americans hesitate to wear them now: Wearing a mask isn’t much fun.

If I left the house in a mask, I’d get puzzled—even suspicious—looks on the street. Pre-COVID-19, I’ve been asked to leave grocery stores, buses, and even a museum because I was wearing a mask.

If I held off, only donning the mask once someone nearby coughed or sneezed, it was no better: the sneezer was often offended and bystanders frightened. Once, at a concert, I put on a mask after someone in front of me started coughing. Security approached and asked me about my “intentions.”

As a researcher of COVID-19 epidemiology at Stanford Medicine, I work with data scientists to monitor and predict how measures such as mask-wearing and social distancing can reduce COVID-19 transmission. It’s heartbreaking and frustrating to see states now scrambling to figure out how to deal with the new surges of coronavirus cases that have followed recent reopenings.

COVID-19 spreads easily. In addition to coughing and sneezing, talking, singing, or even breathing, can spread infectious respiratory droplets well beyond six feet. And COVID-19 is stealthy: almost half of the people who test positive got it from someone who showed no obvious symptoms (not even a mild fever). According to the most current research, between 50 and 80 percent of the people spreading coronavirus feel fine. The only way to really know if someone is infected is by testing—and as a nation, we’re not doing nearly enough.

But we don’t need to know who has COVID-19 to prevent its spread. By capturing droplets before they become airborne, we can stop a respiratory virus in its tracks. Models on similar respiratory viruses suggest that even the simplest masks (like DIY cloth scarves that capture only 20 percent of exhaled droplets) can cut total infections in half. If just 25 percent of Americans used masks that were at least 50 percent effective, like a disposable surgical mask, the epidemic could be nearly eliminated in weeks.

The importance of masks cannot be overstated; in fact, a new study on COVID-19 transmission patterns around the world found that widespread mask-wearing is the most important intervention contributing to successful control of the virus.

In East Asia, we’re raised to value a commitment to the community and family. Yes, this can become stifling—and perhaps a challenge to long-cherished American values of individualism and self-expression. Masking is hardly a new issue; there were anti-mask protests even during the Spanish flu pandemic of 1918-19.

But in a health crisis, placing a premium on communal health—even at the expense of individual expression—is a must.

Recent research suggests that clear plastic face shields, which are more comfortable and allow us to see each other’s faces, might be as effective as masks. Perhaps that’s what we’ll need to adopt over the next several years. But for the time being, covering half our faces is our only real option if we want to be out and about without putting our friends and neighbors at risk.