Moderna to Request COVID Vaccine Authorization for Kids Under 6

Moderna plans to request authorization for its low-dose COVID-19 vaccine for children younger than 6, after initial results from its clinical trial showed that younger children had a similar immune response to the vaccine as young adults.

If authorized, Moderna’s vaccine will be the first to help protect the youngest group of children, who have remained vulnerable to infection throughout the pandemic.

The vaccine prevented symptomatic infection in about 44% of children 6 months to 2 years old, and 37% of children from 2 to under 6 years old. The company reported no severe cases of COVID-19 and no new side effects.

“People who get vaccinated and boosted are truly protected from severe COVID. I think that will play out to be true in the youngest kids all the way through to the very oldest adults,” Paul Burton, MD, PhD, Chief Medical Officer of Moderna, told Verywell. “It's great news for parents. I think it's great news for kids as well.”

In a statement on Wednesday, the company said it will submit its request to the Food and Drug Administration (FDA) “in the coming weeks.”

The announcement comes as cases of Omicron subvariant BA.2 pick up in the U.S. and officials weigh whether to authorize a fourth dose of Pfizer and Moderna’s COVID-19 vaccine for older adults.

Children aged 5 to 11 are currently eligible for Pfizer’s pediatric vaccine. In its announcement, Moderna also said it is seeking authorization for its vaccine to be used in adolescents aged 6 to under 12. The Moderna vaccine is currently only authorized for people aged 18 and older.

How Effective Is Moderna's Vaccine for Young Kids?

To test its vaccine, Moderna immunized 2,500 children between the ages of 6 months and 2 years and 4,200 children between the ages of 2 and 6. Both groups were given two shots a month apart.

Rather than compare disease outcomes between the vaccinated and placebo groups, as is done in vaccine efficacy trials, the researchers performed an immuno-bridging study, measuring how well the shots elicited an antibody response. Nearly all the children in this group produced antibodies at the target level, Burton said, with the youngest children producing a higher level of antibodies.

The dosage for kids under 6 is a quarter of that received by adults inoculated with Moderna’s vaccine: 25 micrograms. In the initial open-label study, Burton said the company tested both a 50- and 25-microgram dose before moving forward with the latter.

“The fact that these youngest kids are able to mount a very strong immune response really bodes well for long-term protection,” Burton said.

The study didn’t show any cases of kids with severe disease, so it’s difficult to know precisely how well the vaccine prevents that outcome, William Schaffner, MD, medical director of the National Foundation for Infectious Diseases (NFID) and professor of medicine in the division of infectious diseases at the Vanderbilt University School of Medicine, told Verywell.

However, because these children demonstrated a high level of antibodies after vaccination, it’s likely that they will be well-protected against severe disease and death, Schaffner said.  

“We know that the antibody titers that have been evoked have worked well in older children, young adults, and older adults,” he said.

Importantly, the study was conducted while Omicron was the primary variant in circulation. The lower efficacy against infection during this period was “as expected,” Moderna said, consistent with observational data in adults.

Is It Safe?

Moderna said the side effects from its vaccine were mild or moderate and reported no severe side effects and no deaths. There were also no signs of multisystem inflammatory syndrome (MIS-C) or myocarditis. Myocarditis, a type of heart inflammation, has been reported in rare cases after vaccination with Moderna and Pfizer’s COVID-19 vaccines, particularly in adolescents.

About 15% of children from 2 to under 6 years had fevers of 100.4 degrees after vaccination, and 17% of children 6 months to 2 years old had the same grade fever. Only 0.2% of children in each age group experienced fevers above 104 degrees.

“Sore arms and fevers and things like that seem to be quite in line with the other vaccines that we give children,” Schaffner said. “The question will be: Exactly how effective is it?”

Working Towards Vaccinations for All Children

In addition to its application for younger kids, Moderna is also requesting emergency use authorization of its vaccine for children aged 6 to under 12. The primary series for this age group would include two 50-microgram shots.

The company added more safety data to its application for adolescents aged 12 to under 18 years, which it submitted last year. It is also testing a booster dose for children from 6 months to 11 years old.

As federal regulators review the data, Burton said he expects Moderna’s vaccine to be authorized across all age groups this spring or early summer.

“We have teams on it constantly, trying to get the data ready and submitted to regulators,” Burton said. “This is a huge priority for us.”

What This Means for Families

The FDA typically calls on a panel of outside advisers to review the data and make a recommendation about whether to authorize a vaccine, though this is not a requirement. Before the vaccine may be administered, the Centers for Disease Control and Prevention (CDC) must also sign off.

Schaffner said he expects the FDA to authorize the vaccine for this age group. If that happens, he thinks the CDC’s advisors will weigh how strongly to recommend the vaccine for young children.

“I think there might well be some discussion in that group as to whether it ought to be routinely recommended, or as part of what has been called 'shared clinical decision-making,'” Schaffner said.

One in 10 parents of children younger than 5 said they would have their child vaccinated “right away” when it becomes available, according to a Kaiser Family Foundation survey from January.

While children are reported as being less susceptible to severe disease than adults, Burton said it’s still important that children get vaccinated, as it remains the most surefire way to bolster immune response against infection.

“If little kids get infected, it can be severe. They may be hospitalized—thankfully, it's at a lower rate—but it's severe,” Burton said.

Protecting children can also be beneficial for limiting viral spread more broadly, he said.

“This age group kind of acts as a reservoir. If we don't vaccinate them, the virus will keep multiplying, potentially mutating, and then infecting older, more vulnerable grannies and grandads,” Burton added.

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