Pfizer and BioNTech now have preliminary data demonstrating safety and efficacy of their Covid-19 vaccine in younger children, the first vaccine to report results from a pediatric study. The companies said they plan to seek emergency use authorization from the FDA soon.
The vaccine for children is given at the same three-week interval as the one for those 12 and older. But the pediatric vaccine is a lower dose; 10 micrograms compared to the 30 micrograms of the shots for the older age group. With this lower dose, the companies reported that the antibody responses in younger children were comparable to those achieved in the 16 to 25 age group at the higher dose. The data have not yet been published. Pfizer said that the companies plan to submit the full Phase 3 data for peer review in a scientific publication.
The Pfizer and BioNTech Covid-19 vaccine, named Comirnaty, was granted full FDA approval last month for those 16 and older. In adolescents age 12 to 15, the messenger RNA vaccine is available under emergency use authorization. But the lack of any vaccine option for younger children leaves them vulnerable to infection from the novel coronavirus.
Pfizer and BioNTech’s Phase 1/2/3 pediatric clinical trial is enrolling up to 4,500 children ages 6 months to 11 who had no prior signs of Covid-19 infection. The study is ongoing at more than 90 sites in the U.S., Finland, Poland, and Spain. Participants were split into three groups based on age: 6 months to 2 years; 2 to 5; and 5 to 11. Children younger than 5 were given a 3 microgram dose for each of their two shots. The preliminary data reported Monday are from 2,268 participants in the 5 to 11 age group, who received the two-dose vaccine regimen at the 10 microgram level.
According to the preliminary data from the Phase 2/3 portion of the clinical trial, the average antibody levels in the 5 to 11 group were roughly comparable to the average antibody levels achieved in tests of the 30 microgram dose in the 16 to 25 age group from a previous clinical trial. That group served as the control for the pediatric study. Pfizer and BioNTech did not say how many cases of Covid-19 were reported in the 5 to 11 age group, which would indicate how much the vaccine would reduce the likelihood of developing infection.
The early data show that the vaccine was well tolerated by children, and the shots produced side effects similar to those reported in the older age group. Those effects included reactions at the injection site, fatigue, headache, muscle pain, chills, and fever. The companies did not say whether there were any reports of myocarditis, which is inflammation of the heart muscle. In the months since the vaccine has been available for those 16 and older, surveillance of side effect reports found that some recipients developed myocarditis. In the rare instances that this side effect was found, it was mainly in males, particularly young males.
The myocarditis risk, and the lack of understanding about it, was cited by an FDA advisory committee last Friday as one of the reasons for voting against recommending a booster shots for those 16 and older. The committee did, however, vote to recommend emergency use of a booster shot for those 65 and older and others who are at high risk of severe Covid-19 infection.
Pfizer and BioNTech said that the early clinical trial results in the 5 to 11 age group support bringing this lower-dose vaccine to younger children. In the U.S., the plan is to first seek an emergency authorization while the studies continue to generate the safety and efficacy data required to support full approval. In Europe, the companies said they will ask for an update to the conditional marketing authorization for the vaccines.
“Since July, pediatric cases of COVID-19 have risen by about 240% in the U.S. –
underscoring the public health need for vaccination,” Pfizer CEO Albert Bourla said in a prepared statement. “These trial results provide a strong foundation for seeking authorization of our vaccine for children 5 to 11 years old, and we plan to submit them to the FDA and other regulators with urgency.”
Pfizer said that preliminary data for the younger two age groups, ages 2 to 5 and 6 months to 2 year, are expected in the fourth quarter of this year.
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