This week, as coronavirus vaccinations for 12- to-15-year-olds began just in time for summer camp, and the Centers for Disease Control and Prevention said vaccinated people could gather indoors without masks, many parents of younger children were left to wonder: When is our turn?

Most will have to wait until at least fall and potentially early 2022 for a coronavirus vaccine to be available to the nation’s approximately 50 million children younger than 12. But for a handful of families, including several in the Washington area, the moment has already arrived.

Pfizer is running a nationwide trial for children 6 months to 11 years old, with one of the sites at the Johns Hopkins Bloomberg School of Public Health in Baltimore. And Moderna is running a trial in the United States and Canada for kids in that age range with a site at the University of Maryland’s School of Medicine that includes locations in Baltimore and Frederick.

As drug companies expand coronavirus vaccine access to children, officials are working to persuade people who are skeptical or unwilling to get vaccinated. (Luis Velarde, Jonathan Baran, Erin Patrick O'Connor/The Washington Post)

Both local trials have enrolled a small number of initial participants to receive lower doses — or in some cases, the same dose as adults — and be monitored for side effects and development of antibodies. The goal is to find the dosage sweet spot by not provoking too strong a reaction while giving children the highest level of protection.

So far, about two dozen area children are in the process of receiving two shots as part of the Pfizer study, which started in late March. In the Moderna study, 10 children received a first dose in late April or May and will get a second after four weeks. More children will be added as the trials progress.

When Carrie Golitko, who has cared for colleagues with covid-19, learned her son and daughter — who are 10 and 8 — had been selected to participate in the Pfizer trial, she could not believe her luck. “I just started crying,” the Takoma Park, Md., pediatrician said. “I was so excited. It was just like a wave of relief washed over me.”

Her children got shots on April 5 and April 26. Her son, Kellan Hayes, 10, said he experienced some temporary chills and a mild fever with brief hallucinations but the payoff was worth it. “I was like the most famous kid in the school,” he said. “Kids came up to me saying, ‘Is it true you got the covid-19 vaccine?’ My mom told us that we’re going to be a part of helping the world and we’re basically making history right now.”

Investigators are scaling the dosing according to age. In the Moderna trial, some children 6 to 11 years old are starting at adult doses or given less; younger children are starting with lower doses. Pfizer is starting children with a third of a dose and scaling up, and then basing younger children’s doses on older children’s responses. The Pfizer vaccine approved last week for 12-to-15-year-olds is the same dose as for adults, but sometimes lower doses are equally effective in children because their immune systems may be more responsive.

Families in the trial monitor their children’s health and side effects, keeping e-diaries and returning to the sites for blood draws to measure antibody response. So far, aside from the expected sore arms and mild temporary symptoms, none of the Moderna participants have reported adverse effects, said James Campbell, principal investigator for the pediatric study for Moderna at the University of Maryland site. The principal investigator for the Pfizer study at the Johns Hopkins site, Kawsar Talaat, said she could not discuss results yet.

The studies are likely to start moving to randomized control trials to measure efficacy by summer, with some children receiving placebos. Pfizer has said it anticipates having results from younger children’s trials as soon as September, but Talaat said the timing “depends on how long it takes to get all the samples and run the assays.” Campbell said randomized trials are projected to start in late summer and continue into winter, with Moderna shots probably becoming available for young children by early 2022.

Vaccines for younger children could fall under the same emergency use authorization as the vaccines for older people, or they could require their own emergency use authorizations or receive full licenses. (Pfizer applied for a full license for its vaccine earlier this month.)

After a year of missed school, play dates, sports and visits with grandparents, many families jumped at the chance to get younger children into trials — and back to normal life.

Amanda Debes’s children, who are 6, 4, and 18 months, started asking her about getting vaccinated in January, when their grandparents did. When the coronavirus pandemic hit, she said, “as little as they are, they know their life changed dramatically.”

Debes, a Takoma Park resident, is an assistant scientist at the Johns Hopkins Bloomberg School of Public Health and has studied vaccines, including the mRNA type, which Moderna and Pfizer are. “I had no fears once it became clear it worked,” she said, adding that this type of vaccine is broken down and cleared quickly in the body.

Getting vaccinated will allow the family to get back to cherished activities such as riding the Metro, which her kids love. On Wednesday, as Debes took her youngest child, Lucy, for her second shot of the Pfizer vaccine, her husband took the older boys, who have already had two doses, to the Baltimore aquarium. “That was their incentive the whole time. That’s their favorite thing. The last time we went was March 3rd of 2020,” she said. The family rejoined the aquarium on Wednesday, and on Thursday they went to Target, their first time in a store in a year. “They spent an ungodly amount of time walking every aisle with my niece and they bought some toys,” she said.

Families in the trials represent a tiny fraction of those interested. More than 3,400 have filled out applications for the Moderna trial, but the final number accepted will be between 100 and 200, Campbell said, adding that in all, the trial will involve about 7,300 children. The Pfizer trial will involve about 4,000 children nationwide, Talaat said, adding that it is not yet clear how many will enroll at the Johns Hopkins site. Both studies are still accepting applications.

Rebecca Calloway of Keedysville, Md., and her husband have applied for their 7-year-old daughter and 2-year-old son to participate in the Moderna trial and are waiting to be called. They had already enrolled their son in a meningitis vaccine trial when he was a newborn. But when their 3-year-old daughter, Ailish, died suddenly in December of complications from undiagnosed Type 1 diabetes, their desire to help advances in pediatrics sharpened.

“Our daughter who passed away was an organ donor, and those organ donor recipients are out in the community and they are relying on herd immunity in order to get by,” she said. Her voice broke as she recalled how other family members were unable to visit the hospital because of coronavirus restrictions as their daughter was dying. “It’s our job to be part of helping to protect children,” she added, “and if we can’t put our money where our mouth is, then what are we advocating for?”

Many parents who signed up for the trials are health-care providers. Some inquired with local universities even before they knew trials would be set up there. All said they felt lucky to have gotten spots, given the small number of initial participants.

This is in contrast to a Novavax trial for 12-to-17-year-olds that Campbell is also running, which he said is struggling to find participants for its 40 slots, most likely because children that age can now get vaccinated broadly.

Some have questioned the ethics of vaccinating children, who are less likely than adults to become seriously ill or die of covid-19, while so many countries around the world still lack vaccines for adults. Some parents say they prefer to wait, nervous about injecting their children with a vaccine that is so new.

Of the more than 583,000 coronavirus deaths in the United States, over 300 have been in children younger than 18 — a small percentage but still a higher number than annual pediatric flu deaths, Campbell said. Children have come down with multisystem inflammatory syndrome in children (MIS-C), a condition in which different body parts can become inflamed, including the heart, lungs, kidneys, brain, skin, eyes or gastrointestinal organs. Some have experienced long-haul covid-19, in which symptoms persist for months, and it is still unclear what neurological effects the disease will have among survivors.

“We see some really sick children,” Campbell said. “We’ve had multiple children who have been very sick in our intensive care units, on ventilators.”

Parents and children described a combination of selfish and selfless reasons for applying to the trials — and a giddiness at getting in.

“We definitely wanted to be part of the solution and help bring an end to this pandemic,” said Ashley Holmes of Mount Airy, Md., whose son, Cameron, 5, received half the adult dose of the Moderna vaccine. “If kids aren’t getting vaccinated, that’s not going to happen.”

When she picked up Cameron from school to go to the trial site, she said, he ran to the car, yelling, “I’m getting my vaccine today!”

“I was so proud of him, he was so brave,” Holmes said. “There was just kind of excitement in the room. Dr. Campbell came in and gave him a huge high-five and said, ‘You’re the first kids in Frederick to get this vaccine.’ ”

For Holmes, the protection was as important. “Most kids are spared the severe consequences of having covid, but there has been this MIS-C in children, and yes, some have died and been hospitalized, and we still don’t know what the long-term ramifications of having covid are as a child. I don’t want my almost-6-year-old to suffer from some kind of long-term issue because of this.”

Aside from a sore arm and a little tiredness, Cameron exhibited no ill effects, she said. “He’s been bragging about it, which is cute. I think he feels just proud of himself. … He’s like, ‘Now I don’t have to wear a mask to school,’ and I’m like, ‘You do have to.’ ”

Even for very young children, there is a sense that they are doing something important. Grey Toia, 4, lives in a multigenerational house in Baltimore and saw his grandparents and parents get vaccinated.

“He’s fascinated by the whole process, how his body works, what the vaccine does,” his mother, Justina Wiggins, said, adding that when he got his shot, the clinic staff bucked him up, saying, “You’re a science hero, you’re amazing, thank you for being a scientist with us here today.”

The fact that the vaccine has already been given to millions of adults gave his parents the confidence to enroll him in the Pfizer trial, said his father, David Toia, an educator. “We see this as being good wards of our community and the city where we live,” he added.

The trial administrators allowed ample time for parents and children to ask questions, Wiggins said. (Grey asked whether his dog Beowulf could get covid. Highly unlikely, the doctors told him.) “They were very clear that we could walk away at any time,” she said.

For some participants, daily life won’t alter radically now.

“It doesn’t change our plans because we should all be erring on the safe side of things anyway,” said Shayne James, an operating room nurse from Frederick whose children — Elias, 4; Amelia, 3; and Parker, 3 — got vaccinated through the Moderna trial. “But I think it is sort of a relief to think that they have potential immunity to it.”

Grey Toia received just one-tenth of the adult Pfizer dose, so his parents intend to keep acting as if he is not vaccinated until they learn more about the efficacy of that dose and whether he needs a booster.

Still, they said, it’s a good feeling to have gotten it into his arm. Noting that a year ago, some were predicting that it could be years before a vaccine would become available, David Toia said, “This vaccine has been the moonshot of our time … and to have one small toe in that universe, it’s a story to tell, and beyond being a story to tell, it’s moving one small step away from the fear.”

Parents interested in enrolling young children in local trials can apply at centerforimmunizationresearch.org (Pfizer) or medschool.umaryland.edu/cvd/trials (Moderna).