Here’s what you need to know:

• Public health experts say you need to wear masks outside, especially when near other people.
• Available research shows wearing masks and social distancing appear to limit the spread of the virus.
• Disposable surgical masks or reusable cloth masks are ideal for everyday use. N95 masks, and other medical-grade respirators, should be reserved for health-care professionals.
• Masks should completely cover your mouth and nose with a snug (but not tight) fit.

A review funded by the World Health Organization and published in the scientific journal Lancet earlier this month concluded staying at least three feet from others and wearing face masks does appear to limit the transmission of the coronavirus. A separate study from Cambridge and Greenwich universities found mass-adoption of face masks could even prevent a second wave of the disease.

Spate of new research supports wearing masks to control coronavirus spread

Covid-19, the illness created by the novel coronavirus, is a respiratory disease that infects the lungs and throat and commonly spreads when people cough, sneeze, breathe and, yes, even sing. When an infected person exhales, they project contagious droplets of the microscopic virus into the air around them. A reusable cloth mask, even if it’s homemade, blunts the spread of those infectious particles. It’s a line of defense, albeit not a perfect one, to stop you from passing the virus to others.

An Axios-Ipsos survey published earlier this month found 50 percent of Americans say they wear a face mask “at all times” when leaving their home while 27 percent report wearing a mask “some, but not all the time.” Only 10 percent of those surveyed said they never wear a mask.

Unless you’re hiking on a trail where “it’s just you and nature,” you should have a face mask on, said Jade Pagkas-Bather, an infectious-disease expert and clinician at the University of Chicago. There’s a “collective responsibility” to wearing a mask in public, Pagkas-Bather said. People can become infectious before exhibiting symptoms of the virus and some never have any of the common symptoms but still test positive for the virus.

“Wearing a mask is about protecting your neighbor not necessarily yourself. But, if we do it universally, then we protect each other,” Pagkas-Bather said over the phone.

CDC urges organizers of large gatherings to “strongly encourage” use of face masks

The Washington Post spoke to half a dozen epidemiologists and infectious-disease experts about when to wear a mask and how the face coverings play a role in curtailing the spread of the novel coronavirus. Many of them stressed masks are not a be-all-end-all solution — covering your mouth and nose help, but people should continue washing their hands with soap and water for at least 20 seconds. If you’re traveling and you won’t be around running water, be sure to pack some hand sanitizer.

There’s a reason public health officials recommend such stringent mask policies in public, with few exceptions. Epidemiologists understand how the virus commonly travels, and there are clear examples of “super-spreading” events where one person ends up infecting dozens. Last week, there was a reported outbreak at a table tennis club in South Korea. These incidents often happen inside where people aren’t wearing masks, but there’s no definitive research to say when a person is absolutely out of harm’s way.

“There’s not like a magic number or distance that we know of, at least, where once you get beyond radius ‘X’ you’re golden,” said Kimberly Powers, an epidemiologist at the University of North Carolina.

Instead, people should try to mitigate the risks they can control by using what we do already know about the disease, Powers said.

The CDC recommends covering your face while out in public, but the options available range from wearing simple bandannas to buying surgical masks. Children younger than 2 and anyone who already has trouble breathing should not wear a face mask.

The general public does not need to use N95 respirators, the personal protective equipment used in hospitals that provide a tight seal around the mouth and nose, according to Saskia Popescu, an infectious-disease epidemiologist from George Mason University. Health-care workers are at higher risk for exposure because they’re in contact with infected patients for “prolonged periods of time,” but many people will never need to protect against that “level of exposure,” Popescu said.

Answers to your DIY face mask questions, including what material you should use

Any surgical or reusable cloth mask you buy should cover your face from the bridge of your nose to your chin, Popescu said.

“You want it to be snug but not really digging into your skin,” Popescu added.

Experts recommend putting on a mask before you leave your house, apartment or car and enter a public space. Try not to fidget with or take your mask off while outside because the front of the mask may already be contaminated.

Once you’re back home, remove the masks using the straps or elastic on the back of your head and promptly wash your hands with soap for at least 20 seconds. The CDC also advises washing face coverings after every use with warm water, detergent and the highest heat setting on a dryer, if possible. Because of this, you’ll want to use cloth masks that stand up to frequent washes.

As the summer heats up, states are beginning to lift restrictions on businesses and restaurants, but Popescu said that doesn’t mean you should leave your mask at home. Instead, keep an eye on the number of cases reported in your area by public health officials.

“Just because a state is reopening does not mean they have no covid cases,” Popescu said. “You still need to be really vigilant about wearing your mask and social distancing, staying home when you’re sick.”