It’s time to upgrade your mask, public health experts say

As another crushing wave of COVID-19 hits New England, public health experts are pushing a message well tested by time: Wear a mask.

Governor Charlie Baker on Tuesday issued an advisory — but not a mandate — to mask up in public indoor spaces. And several Massachusetts communities, including Boston, have enacted mask requirements of their own in the hope of tamping down the surge of cases and hospitalizations.

“We updated the face covering advisory today to urge all residents to wear a mask in public indoor spaces,” Baker said during a State House briefing. “We’ll continue to release the best public health [guidance] we have, so people can make informed decisions about how to protect themselves.”

But through two years of the pandemic, mask guidance has varied widely. How and when should you mask now?

Here’s what four physicians and infectious disease experts had to say.

Which mask should you wear?

Toss out your cloth mask, experts say.

Quality face coverings — namely surgical and KN95 masks — are “essential” to keep the virus at bay, said Dr. Philip Landrigan, director of the program for Global Public Health and the Common Good at Boston College. “But any mask is better than no mask.”

The snug, medical alternatives will block aerosol particles more effectively than cloth coverings and provide greater protection against Omicron, the highly transmissible strain that has quickly become the dominant variant. It accounted for 73 percent of US cases between Dec. 12 and 18, according to the CDC.

Dr. Abraar Karan, an infectious disease doctor at Stanford University, advised people to avoid cloth and loose surgical masks that allow particles to enter the nose and mouth. If no alternatives are available, use a brace to tighten the mask, he said.

Tufts University professor and World Health Organization adviser Dr. Daniele Lantagne said the efficacy of looser masks can also be improved by twisting the ear ties or tying a mask behind your head.

Only cloth masks and undamaged and dry surgical masks can be reworn, she added in an e-mail. KN95 are “not optimal to rewear, but possible” if they are cleaned thoroughly.

Regardless of which masks people choose, masking is a vital component of the “Swiss cheese model of protections” the state has enacted to fight the virus, which also includes vaccine awareness and testing protocols, Lantagne said.

“In light of the Omicron variant that is both more transmissive and can escape the vaccine, wearing a mask becomes an even more important part of our response,” she added.

Should you hunt for N95 masks?

Karan said a hospital-grade N95 mask is “the best option.”

But public health officials have steered the community away from N95 masks in the past, looking to save the supply for hospital staff in contact with COVID-19 patients. (Karan said N95 shortages are rare now.)

Lantagne did not recommend N95 masks because they are difficult to properly fit and seal without professional oversight. “Yes, they provide the best protection,” she said. “But they are not intended for the community, and an unsealed N95 is almost as good as nothing.”

Should you double mask?

If your mask doesn’t fit properly, yes. Wearing two face coverings can “make the masks press more tightly against your face,” Lantagne of Tufts said, which lowers your chances of coming into contact with virus-containing droplets.

The Centers for Disease Control and Prevention suggested double masking in February, though studies conducted since have found that the practice could make the coverings difficult to breathe through.

When should you wear a mask?

In crowded, indoor spaces, masking is a must, said Dr. Sabrina Assoumou, an infectious disease physician at Boston Medical Center who has advised Boston city officials on COVID-19 guidance.

Dozens of cities have made masking a requirement indoors or in municipal buildings, and Rhode Island Governor Dan McKee authorized a mask mandate for indoor venues of 250 or more people on Dec. 15.

Masks are also required on planes, trains, buses, and public transportation across the country, as well as in transportation hubs like airports and train stations. (Here are other travel requirements and recommendations.)

Landrigan said those gathering with vaccinated family members during the holidays can drop mask-wearing, especially if everyone produces a negative test result shortly before meeting. Keep note: Rapid and PCR tests are in high demand this season.

Outdoors, people should feel free to go bare-faced, Assoumou added.

Why should you wear a mask?

Preliminary research has found that the Omicron variant is significantly more infectious than previous iterations of the virus and can evade vaccines, Assoumou said. Its aggressive qualities mean that the strain could potentially overwhelm the health care system.

Hospitals in Massachusetts are already accommodating a flood of patients — many of whom are unvaccinated. Some facilities in Rhode Island are “currently collapsing.”

Masking, along with vaccination, can help lower the number of hospitalizations and, ultimately, deaths.

“If you can wear a good mask right now, you’re doing the service to everybody because you will ensure fewer people get sick, end up in the hospital, or die,” Karan said.

Is a statewide mask advisory enough?

Baker’s refusal to issue a mask mandate in Massachusetts has drawn a mix of reactions.

Assoumou called the advisory “a good first step” in the quest to encourage universal masking. “Still, mandates are the way governments signal to the public that something is important and necessary.”

In a press conference with a dozen public health experts Tuesday afternoon, state Senator Becca Rausch took a stronger stance. She said the indoor mask “suggestion” is a “nonbinding, nonmandatory recommendation that runs directly contrary to recommendations from public health officials and medical experts here in Massachusetts, nationally and even globally — all of whom say we need a mandate.”

Massachusetts Senate President Karen E. Spilka agreed.

“I believe it’s necessary to go beyond advisories and recommendations and apply a uniform, consistent approach to stopping the spread and saving lives,” she wrote in a statement. “I am calling on the administration to reinstitute a statewide indoor public mask mandate, increase efforts to achieve vaccine equity and require proof of vaccination for most public indoor social venues.”