As much as ballet artists and audiences welcome the return of “The Nutcracker” — as a reliable provider of holiday cheer and absolutely essential box office receipts — staging the ballet this season is a delicate undertaking, and there’s nothing predictable about it.

“There’s a lot of excitement and a lot of anxiety, frankly,” says Lourdes Lopez, artistic director of Miami City Ballet. She’s readying her company’s production for a Kennedy Center run Nov. 24-28.

“The unknown continues,” she says.

So much is unknown this season, as the coronavirus continues its course, and stage productions everywhere are operating in fear of outbreaks and quarantines. No one wants to relive the painful shutdowns of last year. Ballet companies have a very large task here; they must navigate mandates and protocols to keep performers, crew, staff and audiences safe during what is arguably the most difficult ballet in the canon to manage.

For most companies, “The Nutcracker” is the most-performed production of the year, a marathon of shows going on week after week, with scores of children added to the cast, and the professional dancers rotating in and out of roles from one night to the next at a dizzying pace. Backstage space typically fills with extra staff applying makeup to squealing little faces. Dancers routinely cluster in the wings to cheer on their colleagues. After the show, friends and family members converge on dressing rooms for kisses and hugs. Let’s not forget that it’s also cold and flu season.

Kids, crowds, huffing, puffing. Shared mouse heads, borrowed tubes of lipstick. “The Nutcracker” could be a covid-19 nightmare. Every “Nutcracker”-dancing troupe on the planet is working hard to make sure that doesn’t happen.

So what will that look like to audiences?

I’ve spoken with ballet officials and artists to find out what changes are in store as they prepare their Sugar Plum Fairies and waltzing Snowflakes for live theater audiences for the first time in two years. In some cases, there will be slightly smaller casts. Many companies, having required their dancers to be vaccinated, are limiting their youngest student performers to 12 and older, to ensure that the entire cast is fully vaccinated by opening night.

The Washington Ballet, however, is keeping to tradition, with children as young as 6 in its Washington-themed “Nutcracker,” created by the company’s former director, Septime Webre. But it has scheduled fewer performances (30, instead of 45 to 50) at the Warner Theatre, where the ballet can be seen Nov. 27-Dec. 26. Dancers younger than 12 will be wearing custom-designed masks to match their party frocks, clown costumes and mouse fur. These kids will also need a negative coronavirus test 72 hours before any performance in which they’re dancing, says artistic operations manager Catherine Eby. All the professional dancers are vaccinated, and they are tested weekly.

The same goes for children younger than 12 in Miami City Ballet’s production, choreographed by George Balanchine. Artist Ruben Toledo, who created the company’s sets, has designed masks to coordinate with the costumes devised by his late wife, fashion designer Isabel Toledo. But there will be no children’s chorus in the Snow Scene — that would crowd the musicians in the orchestra pit.

Pit considerations are also why San Francisco Ballet is closing off the first two rows of the orchestra section in the War Memorial Opera House, to prevent audience members from leaning over the railing at intermission and getting too close to the musicians.

The National Ballet of Canada is bucking precedent by not inviting stars of the Toronto Raptors basketball team or other local celebrities to fire the cannon in its battle scene. That’s to avoid the agony of uncertainty, at least as much as possible.

“We don’t want people backstage who don’t absolutely have to be here,” says Associate Artistic Director Christopher Stowell. “One slip of something and suddenly the whole cast of ‘Nutcracker’ has been exposed.”

This year the company has a strictly 12-and-older policy, so a few other characters normally played by 8- and 9-year-olds will be absent.

“I said, ‘No one will notice,’ and everybody jumped on me,” Stowell says with a laugh. “They said, ‘Everyone remembers the little lambs and the baby mice!’ It’s amazing — there’s so much beautiful choreography going on in those scenes, but everyone remembers the mice and lambs the most.”

Some of the health strategies this year must, necessarily, push against dearly held traditions in the ballet world, such as the collective unity of a cast.

“Backstage is a community,” says Lopez. “And you look at how many times you can keep that community from coming together.”

In other words: No sharing makeup. And children will be separately corralled, to limit backstage traffic jams. They’ll arrive at the theater with makeup and hair already done at home, by parents armed with instructions.

Still, putting on “Nutcracker” without small children was unthinkable, Lopez says.

“Part of the charm, the beauty and the magic that ‘Nutcracker’ is about is that it’s a child’s imagination,” she says. “So not to have children, for me, personally, took away from what the ballet means.”

What about the professional dancers? Deprived of live audiences and a busy performance calendar for nearly two years — a cruel interruption of a dancer’s brief career — they are excited and ready to weep for joy on opening night. This is not a praying-for-that-last-show-to-come kind of “Nutcracker” experience.

For these “Nutcracker” lifers, whose autumns and winters have revolved around auditions, rehearsals and performances of the ballet every year since childhood, this one is special.

Washington Ballet member Jessy Dick, for instance, has been soaking her feet in an ice bucket every night, relieving her “Nutcracker” rehearsal pains. It hasn’t been easy to ramp up quickly to what is the most physically taxing production of the season. But she couldn’t be happier.

“It’s a good exhaustion,” the 26-year-old says during a recent break in a long day of drills that included the first time learning the Snow Queen role. “It feels good to be exhausted from pouring your heart out at the studio every day.”

It feels good. For many of the dancers who were sidelined by theater shutdowns and social-distancing mandates, a return to “The Nutcracker” is the surest sign things are back to some semblance of normal. Or, at least, a new and acceptable normal, even though it still includes wearing masks in rehearsals, routine testing and distancing in public areas.

“In the past, sometimes it’s like, ‘Oh, I’ve heard that music over and over again,’ but this year it’s like, ‘Oh, the music!’ ” says Dick. “There’s tutus, there’s pointe shoes. It feels really wonderful to dive back in fully, and ‘Nutcracker’ is the perfect culmination to bring us all back together.”

In the past, conductors, too, might have tired of the ballet’s familiar score, but the Tchaikovsky has renewed value now. San Francisco Ballet Director Helgi Tomasson says that in a recent “Nutcracker” meeting with his conductors, one of them acknowledged that he had once longed for a year off from hearing the music, but he now can’t wait to get back in the pit with that score again.

“It’s a feeling of the rebirth of ‘Nutcracker,’ ” says Tomasson, reflecting on the buzz in his studios. “Coming back to it under the pressure of last year and everything we went through, it’s going to feel like the world premiere of ‘Nutcracker.’ ”

Emotions are high — no matter the hectic pace, the uncertainties, the weeks and weeks of rehearsals in sticky, cumbersome masks.

“You don’t get used to dancing in a mask,” Dick says. “For an extended period of time something’s on your face and you want to take a big breath and you can’t. But the positive of it is, we’re all tired together, we’re all pushing together. . . . Everybody feels that collective soreness of being in pointe shoes for six hours a day. Everybody had to re-remember what it’s like to be a dancer.”

Says the National Ballet of Canada’s Stowell: “We’re still getting into the kind of shape required to work this fast, this hard, with this intensity. But the other side of it is I don’t see people holding back out of a sense of wanting to be perfect. They’ve been denied what they love for so long, they’re not worried about perfect.

“There’s a refreshed love for it this year,” he adds. “A realization of how much it means to them and how much they care about it.”