Vaccinologist Dr. Greg Poland discusses what happens after the first dose of COVID-1

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There are not enough teenagers to register for the Moderna COVID-19 vaccine trial, a federal official said this week, potentially delaying the authorization of vaccines for this age group.

Last month, the US Food and Drug Administration approved the use of the Pfizer-BioNTech vaccine for children between the ages of 16 and 17, as well as adults. The companies do not have enough data on younger adolescents to apply for use in this age group, and Moderna has only tested its vaccine in adults, so it is only allowed for those aged 18 and over.

About four weeks ago, Moderna launched a study of 12- to 17-year-olds, but apparently the company is struggling to find enough adolescent volunteers.

Moncef Slavey, scientific director of Operation Warp Speed, the government’s vaccination effort, said Tuesday that while the adult vaccine trial recruits 800 volunteers a day, the teen trial receives only about 800 a month.

The study needs at least 3,000 participants, he said, to provide valid safety and efficacy data and obtain FDA approval.

“It’s really important for all of us, for the entire population of America, to realize that we can’t have this guidance unless adolescents between the ages of 12 and 18 decide to participate,” Slavey said.

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Although teenagers do not usually get very serious cases of COVID-19, they can get sick and transmit the virus that causes the disease. More than 2 million juveniles were diagnosed with COVID-19 in 2020 and are much more likely to have contracted the disease but have never been diagnosed.

This fall, U.S. counties with large colleges or universities where full-time classes were held saw a 56 percent increase in COVID-19 cases after classes began, and students set fire to the top 19 hotspots in the United States during the fall semester.

Children and adolescents may not bear much of the burden of the infection, but they “carry a disproportionate burden from the overall impact of the pandemic,” said Dr. Lee Savio Beers, president of the American Academy of Pediatrics and professor of pediatrics at Children’s National Hospital. “We shouldn’t forget that.”

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Children’s learning is disrupted, along with their social life and extracurricular programs. It happens at a time when their brains are still growing and developing, “there is the potential for much longer-term effects on them” than in adults, Beers said. “It really is a crisis situation.”

While COVID-19 is usually mild in children, it can rarely cause serious illness or even death. At least 172 American children died of COVID-19 as of December 17, compared with 166 who died of influenza during the 2019-2020 flu season.

A Pfizer spokesman said the company hoped to have data from 12-15-year-olds earlier this year and then, based on those findings, could begin testing on younger children in the spring.

For her part, Moderna said her process was going well. “While enrollment was lower during the holiday season, we expect to see an increase in the new year as planned. We are on track to provide updated data around mid-2021,” an email spokesman said. (More details on the trial period are available here.)

Vaccines are usually tested in adults and then in teenagers before being tested on younger children and babies who may need lower doses or have different reactions.

Dr Yvonne Maldonado, an expert in infectious diseases and global health at Stanford University School of Medicine, said it was crucial to obtain data on vaccines for children of all ages.

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“Many of us want to see children vaccinated – of course for their own safety, but also because it really reduces the transmission chain,” said Maldonado, chairman of the American Academy of Pediatrics’ Infectious Diseases Commission.

But the fact that COVID-19 is usually so mild in minors makes it difficult for parents to justify enrolling their children in trials, she said.

“If the disease was something that clearly affected them in an extremely negative way, you will probably see more interest there,” she said.

It will take time to gain momentum in the process of Modernism and that is why

Even if parents want their children to participate, it can be difficult to get a busy teenager involved in the two-shot process. “It’s a pretty rebellious group in general,” said Maldonado, a mother of three who has grown up.

By law, children over the age of 7 must agree to participate in a trial, even if their parent unsubscribes from it.

The test volunteers received two shots of the vaccine at 3-4 week intervals and their blood was taken several times.

However, there are many parents and teens who want to participate in vaccine trials, said Dr. Barbara Pahud, a pediatric infectious disease specialist and director of research at the Infectious Diseases Unit at Children’s Hospital of Mercy in Kansas City.

Pahud is not yet helping to conduct pediatric research, but she plans and expects that many people in her community and elsewhere will want to join when information about the trials comes out.

“In a month, the situation may look very different,” she said.

Pahud said she was not surprised that Moderna took longer to sign for teenagers than for adults. Pediatric studies, she said, are simply being used at a slower pace. “There’s no reason to expect them to sign up at the same rate as adult trials,” she said.

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The federal government and vaccine manufacturers have not placed as much emphasis on testing vaccines in children or pregnant women as they have in adults, Pahud said – without including any group in the initial studies – and that needs to change if they want to speed up the pace.

Dr. Robert Frank Jr., director of the Center for Vaccine Research at Cincinnati Children’s Hospital Medical Center, said he was also not surprised that enrollment so far has been slow in the Modern process.

“Whenever you move to a new age group for a vaccine, it takes a while to gain momentum,” he said in an email.

The weather also makes it difficult to vaccinate minors, he said. While clinical trials are usually conducted during the workday, children are not available until the end of school hours, which reduces the time required to enroll, he noted.

Frank, who is helping Pfizer test the teen, said his pace was slow at first.

“But since the teenagers signed up, they told their friends a lot about the study, which significantly increased the recording,” he said, adding that he expected the same to happen with the Modern process.

If they can stick to current schedules, both vaccines may be available to adolescents before the start of the 2021-22 school year, although it remains unclear when they will be approved for use in younger children.

Contact Karen Weintraub at

Patient health and safety coverage at USA TODAY is made possible in part through a grant from the Masimo Foundation for Health Ethics, Innovation and Competition. The Masimo Foundation does not provide editorial data.

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