Mar. 29, 2021 -- As more adults across the country get vaccinated against COVID-19, researchers are turning their attention to studying the vaccine in children and teens. Trials are now underway in the U.S. in children as young as 6 months.

Here, experts address some frequently asked questions about the COVID-19 vaccines for the younger population.

Are COVID vaccines really needed for children, since they are less likely to get severely ill?

Yes, they are needed, experts agree.

"We know kids are not as affected, but it's inaccurate to say it's a benign condition in kids," says Sean O'Leary, MD, vice chair of the American Academy of Pediatrics Committee on Infectious Diseases and a professor of pediatrics at the University of Colorado Anschutz Medical Campus. "We need a vaccine for kids to protect them. Younger kids appear to be less likely to get COVID and spread it than adults, but adolescents look more like adults in terms of getting it and spreading it."

Protecting children is crucial, agrees Yvonne Maldonado, MD, chair of the American Academy of Pediatrics Committee on Infectious Diseases and chief of pediatric infectious diseases at the Stanford University School of Medicine. "There are millions of infected children, thousands of hospitalizations, and over 260 deaths in children," she says.

As of March 18, 3.34 million children in the U.S. have had COVID-19, according to the American Academy of Pediatrics.

Besides protecting children from infection and death, "the other issue is the whole idea of herd immunity," O'Leary says. Reaching herd immunity against COVID-19, experts agree, will require that 70% to 85% of the population be immune either due to vaccination or previous infection.

About 23% of the U.S. population of 331 million, or about 76 million, are under age 18. "We are going to have to vaccinate children to reach herd immunity," says Tina Tan, MD, a pediatric infectious disease specialist at Lurie Children's Hospital of Chicago and a professor of pediatrics at the Feinberg School of Medicine at Northwestern University.

Which companies are testing a COVID vaccine for children?

As of March 25, Pfizer-BioNTech and Moderna have launched clinical trials of their COVID vaccines in children as young as 6 months, in older children, and in teens. Pfizer's vaccine has an FDA emergency use authorization for people ages 16 years and up; Moderna's has an EUA for those ages 18 and older.

Moderna's newest trial, called the KidCOVE study and launched in mid-March, will test its vaccine in children ages 6 months to less than 12 years. It will test two or three dose levels, depending on the age, given in two shots 28 days apart. Moderna plans to enroll about 6,750 children in the U.S. and Canada for this trial, with some children getting the vaccine and others a placebo.

Moderna launched another trial in December, enrolling 3,000 participants ages 12 to 17. It is comparing a dose of the vaccine with a placebo.

Pfizer-BioNTech completed enrollment of 3,000 adolescents in its COVID vaccine trial in late February. On March 25, it announced plans to launch a trial in children ages 6 months to 12 years. It will first study the best doses in 144 children, and in later stages will enroll another 4,500 participants in the U.S. and Europe.

Will the vaccines for children be different than those for adults?

The same vaccines are being tested in children as in adults. Moderna and Pfizer are messenger RNA (mRNA) vaccines. The vaccines instruct our cells to make a harmless piece of what is known as the spike protein. This is the protein found on the surface of the coronavirus that causes COVID-19. The body learns to fight off the real infection when it shows up.

As for doses in younger people, "that's what they are working on right now, trying to sort those things out," says O'Leary.

For other vaccines, he says, the dose is usually but not always the same in children as in adults, he says. But "sometimes, kids have a more robust immune response to vaccines, so they may need a lower dose."

When will the vaccines likely be ready for children and teens?

Predicting whey they’re available is always a moving target, but Tan estimates that by this fall, 12- to 17-year-olds will have some vaccine ready for them. Since the trials for those under 12 are just starting, she says, "We don't expect data [on results] until the end of 2021 or early 2022." She estimates that the vaccine for kids under 12 might start to be available the second half of 2022, with those ages 6 to 11 getting vaccinated first, then children ages 2 to 5 years, followed by those ages 6 months to under 2 years.

Infants and young children may have some protection even before vaccination. "We know if moms are vaccinated, their antibodies are transmitted through the placenta to the baby, and through breast milk," Tan says.

Are children expected to have the same side effects as adults?

This is not yet known, Tan says, but information on them will be collected as the trials continue.

Trial researchers will monitor safety and adverse events and evaluate doses so children have the lowest protective dose, Maldonado says. She agrees that the side effect profile isn’t known yet. "It is unknown whether children will have more or less side effects, but [there have been] no up-front concerns."

Are vaccines likely to be mandated for children for school entry?

That is also yet to be determined, but the decision to make vaccines mandatory for school entry is a state government decision.

In Maldonado's view, "I don't think vaccine mandates are important at this time. We should see how the vaccine rollout goes at this time and adjust our vaccine recommendation as we see the next steps of the pandemic."

The American Academy of Pediatrics does not yet have a stance on mandates.

So far, Maldonado says, "we are seeing a tremendous response from parents in our communities who want their children to be vaccinated."

Show Sources

News releases, Moderna: "Moderna Announces First Participants Dosed in Phase 2/3 Study of COVID-19 Vaccine Candidate in Pediatric Population," "Moderna Announces First Participants Dosed in Phase 2/3 Study of COVID-19 Vaccine Candidate in Adolescents."

Clinical "Study to Describe the Safety, Tolerability, Immunogenicity, and Efficacy of RNA Vaccine Candidates Against COVID-19 in Healthy Individuals."

Tina Tan, MD, pediatric infectious disease specialist, Ann & Robert H. Lurie Children's Hospital, Chicago; professor of pediatrics, Feinberg School of Medicine, Northwestern University.

Sean O'Leary, MD, professor of pediatrics, University of Colorado Anschutz Medical Campus; vice chair, American Academy of Pediatrics Committee on Infectious Diseases.

Yvonne Maldonado, MD, chair, American Academy of Pediatrics Committee on Infectious Diseases; chief of pediatric infectious diseases, Stanford University School of Medicine, Stanford, CA.

American Academy of Pediatrics: "Children and COVID-19: State Level Data Report." "SARS-CoV-2 antibodies detected in human breast milk post-vaccination," "Newborn antibodies to SARS-CoV-2 detected in cord blood after maternal vaccination."

© 2021 WebMD, LLC. All rights reserved. View privacy policy and trust info