Amid the ongoing surge of COVID-19 cases across the Monadnock Region, health experts continue to stress the importance of donning a face mask.

Here’s a rundown of what type to wear and when:

Who should be wearing a mask and when?

Everyone 2 years or older, regardless of vaccination status, should wear a mask in indoor public places in communities with substantial or high transmission of the virus, according to the Centers for Disease Control and Prevention.

Like the rest of New Hampshire, Cheshire County has a high transmission rate, the federal agency’s data show.

In mid-December, Keene reinstated its mask ordinance, which exempts children under 10 and anyone with a medical or developmental condition that makes wearing a mask unsafe.

Within the Elm City, masks are required at all indoor public spaces except for fitness centers that charge membership fees, some indoor performance venues and people sitting at a restaurant or bar.

Dr. Aalok Khole, an infectious disease physician at Cheshire Medical Center in Keene, said Monadnock Region residents should still wear masks in those exempted circumstances, aside from when actually eating or drinking.

What type of mask will best protect me against COVID-19?

Finding a good mask, according to Khole, boils down to two things — fit and filtration.

“A mask that fits snugly around the nose and chin with no large gaps around the sides of the face, has multiple layers, has breathable material so it is comfortable to wear for long hours is the ideal mask,” he said in an email.

That includes surgical masks, good-quality cloth masks and N95s.

However, with the latter, Khole said the mask needs to be “fit tested” to work to its fullest capacity.

“They work best when there are no air leaks,” he explained. “That is usually determined through an appropriate process that healthcare workers go through.”

If a fit test isn’t possible, or you’re unsure of how to do one, Khole said people can make modifications to the mask, like tying knots to the ear loops to enhance the fit, or double mask — with a surgical or N95 mask underneath and a cloth mask on top — to enhance filtration.

Masks that should not be used include repurposed scarves, masks with exhalation valves or vents, gators, single-layered masks or masks made with plastic, leather or loosely woven fabric, according to Khole.

Is wearing a cloth mask still effective, given the contagiousness of the omicron variant?

Experts have voiced different opinions on the efficacy of cloth masks when it comes to omicron.

One, Dr. Leana Wen, an emergency doctor, visiting professor at George Washington University and CNN medical analyst, told that outlet last month that there is “no place for them” amid the highly infectious variant.

If you can, Khole said surgical masks are a good option to incorporate into everyday life. But if they are too expensive or hard to find, he said utilizing a cloth one will still be effective.

He added that an N95 may not be necessary for everyone.

“I surely don’t intend to wear one in any public setting because I know my risks, immune status and the fact that I am vaccinated and boosted,” Khole explained. “Taking these things into consideration before deciding which mask is appropriate for you is crucial.”

If I use a disposable mask, how long can I use it before discarding it?

Technically, Khole said, any disposable mask should be thrown out after a single use. However, given supply constraints and the unusually high demand for them, he said it’s fine to reuse them a few times.

“In simple terms, if the mask is soiled, moist, used for long durations, put on and taken off several times, crumpled, or has been set down in unsanitary areas, its fit and filtration may be affected,” Khole said. “It’s best to discard and get a new one.”

Cloth masks are often reusable and should be washed as soon as they become dirty, according to the CDC. (Read more on this topic on page B3.)

Olivia Belanger can be reached at 352-1234, extension 1439, or obelanger@keenesentinel.com. Follow her on Twitter @OBelangerKS.

Olivia Belanger is the health reporter for The Sentinel, covering issues from the opioid crisis and the COVID-19 pandemic to mental health services in the region. A N.H. native, she joined The Sentinel team in August 2019.