(CNN) — In a highly anticipated announcement, Pfizer said Monday that a phase 2/3 trial showed its COVID-19 vaccine to be safe and elicited a “robust” antibody response in children ages 5 to 11.
These are the first such results published for this age group for a COVID-19 vaccine in the US, and the data has not yet been peer-reviewed or published. Pfizer said it plans to submit to the US Food and Drug Administration (FDA) for an emergency use authorization (US) soon.
The trial included 2,268 participants aged 5 to 11 years and used a two-dose regimen of the vaccine given 21 days apart. These trials used a 10-microgram dose, lower than the 30-microgram dose that has been used for those over 12 years of age.
“The 10 microgram dose was carefully selected as the preferred dose for safety, tolerability and immunogenicity in children 5 to 11 years old,” Pfizer said in a news release.
Participants’ immune responses were measured by looking at levels of neutralizing antibodies in the blood and comparing those levels with a control group of people aged 16 to 25 who received a two-dose regimen with the largest dose of 30 micrograms. Pfizer said the levels compare well to those of older people who received the higher dose, demonstrating a “strong immune response in this cohort of children one month after the second dose.”
“Additionally, the covid-19 vaccine was well tolerated, with side effects generally comparable to those seen in participants ages 16 to 25,” the company said.
A Pfizer spokesperson also confirmed that there were no cases of myocarditis, a type of inflammation of the heart that has been linked to mRNA vaccines.
Pfizer said that this data will be included in a “short-term submission” for the US and that companies will continue to accumulate the data necessary to apply for FDA approval for people ages 5 to 11.
The Pfizer / BioNTech vaccine is currently approved for persons 16 years of age and older, and licensed for use in persons 12 to 15 years of age.
Pfizer said it expects test data for children as young as 6 months “as early as the fourth quarter of this year.”
“Since July, pediatric COVID-19 cases have increased by approximately 240% in the US, underscoring the need for public health vaccination. The results of these trials provide a solid basis for requesting authorization from our vaccine for children ages 5 to 11, and we plan to send them to the FDA and other regulators urgently, “said Albert Bourla, president and CEO of Pfizer, in the statement.
FDA Acting Commissioner Dr. Janet Woodcock and Dr. Peter Marks, director of the FDA’s Center for Biological Research and Evaluation, said in a statement this month that the agency would review data on a vaccine for younger children. “as quickly as possible, probably in a matter of weeks rather than months” once it is submitted for clearance.
“However, the agency’s ability to review these submissions quickly will depend in part on the quality and timeliness of the manufacturers submissions,” they wrote.
Requests for a COVID-19 vaccine for younger children have grown stronger in recent months as cases among children have risen.
Coronavirus infections have increased “exponentially” among children in the United States and now account for nearly 29% of all reported cases nationwide, the American Academy of Pediatrics reported last week.
Still, US health officials have emphasized that children are not just young adults, and even those approaching 12 years old should not receive the largest dose of vaccine available to older people.
“We don’t want children to have adverse effects. Of course, we want them to be able to get vaccinated as quickly as possible, but let’s get it right,” the FDA’s Marks said in a fireside talk hosted by the ResearchAmerica Alliance last week.
“There is a difference here because they are not just getting the same dose of the same age as a person 12 years or older. They have to get a reduced dose. And that is why it is not a good idea for doctors to take things in his own hands right now. “