- Moderna plans to submit an application to the Food and Drug Administration for emergency use of its COVID-19 vaccine in younger children.
- Given the lower effectiveness of two doses against infection, a third dose may also be needed in younger children.
- The clinical data from these trials have not yet been peer-reviewed.
Moderna announced Wednesday that it plans to submit an application to the Food and Drug Administration for emergency use of its COVID-19 vaccine in children 6 months to under 6 years of age.
No COVID-19 vaccines are authorized in the United States for this age group.
The company also released interim results from two phase 2/3 clinical trials — in children 6 months to under 2 years and in children 2 years to under 6 years.
These showed that two doses of the pediatric vaccine generated similar immune responses in young children, as seen with the two-dose series given to 18- to 25-year-olds.
The dose given to younger children was one-quarter of what is given to adults.
“Given the need for a vaccine against COVID-19 in infants and young children, we are working with the U.S. FDA and regulators globally to submit these data as soon as possible,” Moderna CEO Stéphane Bancel said in a statement.
The clinical data from these trials have not yet been peer-reviewed.
In children 6 months to 2 years, two doses of the Moderna vaccine were 43.7 percent effective against symptomatic infection. In children 2 to under 6 years, they were 37.5 percent effective against infection.
This is much lower than the efficacy against infection seen in the original clinical trials of the mRNA vaccines for adults.
But those initial studies were done before the appearance of Omicron, which has mutations that allow it to evade some of the immune protection offered by the vaccines and prior infection.
Moderna’s clinical trials in younger children were carried out when Omicron was the dominant variant, the company said.
Real-world studies in adults show that two doses of the mRNA COVID-19 vaccines offer less protection against infection by Omicron than they did against the original strain of the coronavirus.
However, two doses still offer
There were no severe cases, hospitalizations, or deaths in Moderna’s clinical trials in younger children, so the company cannot estimate how much protection the vaccine offers against those outcomes.
The company said the side-effect profile of its vaccine was favorable and was similar to what is seen in older children, adolescents, and adults.
Most side effects in younger children were mild or moderate and more frequent after the second dose. The company said the rates of fever were similar to what is seen with other pediatric vaccines.
No children developed inflammation of the heart or in the tissue around the heart — myocarditis or pericarditis — after vaccination.
There were also no reported cases of multisystem inflammatory syndrome, or MIS-C, which children can develop after coronavirus infection.
Given the lower effectiveness of two doses against infection, a third dose may also be needed in younger children.
In December, Pfizer and BioNTech announced that their COVID-19 vaccine trial in children 6 months to under 5 years of age would also test a third dose in this age group.
This came after interim data showed that two doses of the companies’ vaccine offered low protection against coronavirus infection in this age group.
Moderna announced on Wednesday that it is preparing to study booster doses in all children and adolescents. This includes testing a booster dose tailored for the Omicron variant.
“No one should view the trial as a failure, especially given that the data released is based on a dose schedule of two doses, not three,” said Dr. Christina Johns, pediatrician and senior medical adviser at PM Pediatrics.
Also, “it should be noted that in many flu seasons, a successful flu [vaccine] efficacy is considered similar to these percentages,” seen in the Moderna pediatric trials, she added.
Parents of young children have been waiting a long time for a COVID-19 vaccine — through the Delta wave and the bulk of the Omicron wave. They are still waiting as much of the country drops COVID-19 mitigation measures.
“The announcement [that] Moderna is seeking emergency use authorization for its COVID-19 vaccine for children younger than 6 is welcome news for millions of parents waiting to get their young children vaccinated,” Dr. Diego R. Hijano, an infectious disease specialist at St. Jude Children’s Research Hospital, said in an email statement.
“Parents should not delay any longer once it is authorized and get their child vaccinated against this life-threatening disease,” he added.
By the time the FDA reviews Moderna’s data, the surge caused by the Omicron BA.1 sublineage may be over.
But Johns said there are signs of another potential surge in the United States, this one being driven by the BA.2 Omicron sublineage.
“We have no way to predict future upticks or surges in cases, so protecting as many persons of all ages that we can is an important initiative,” she said.
Moderna also said on Wednesday that it has initiated an FDA submission for emergency authorization of its vaccine in children 6 to under 12 years of age.
Moderna’s vaccine has been authorized for this age group in Canada, Europe, and Australia.