(CNN) – In a highly anticipated announcement, Pfizer said on Monday a Phase 2/3 trial showed its Covid-19 vaccine was safe and generated a “robust” antibody response in children ages 5 to 11.
These are the first such results released for this age group for a US Covid-19 vaccine, and the data has not yet been peer-reviewed or published. Pfizer said it plans to submit to the US Food and Drug Administration for emergency use authorization soon.
The trial included 2,268 participants ages 5 to 11 and used a two-dose regimen of the vaccine administered 21 days apart. This trials used a 10-microgram dose — smaller than the 30-microgram dose that has been used for those 12 and older.
“The 10 microgram dose was carefully selected as the preferred dose for safety, tolerability and immunogenicity in children 5 to 11 years of age,” Pfizer said in a news release.
Participants’ immune responses were measured by looking at neutralizing antibody levels in their blood and comparing those levels to a control group of 16- to 25-year-olds who were given a two-dose regimen with the larger 30-microgram dose. Pfizer said the levels compared well with older people who received the larger dose, demonstrating a “strong immune response in this cohort of children one month after the second dose.”
“Further, the COVID-19 vaccine was well tolerated, with side effects generally comparable to those observed in participants 16 to 25 years of age,” the company said.
A Pfizer spokesperson also confirmed that were no instances of myocarditis, a type of heart inflammation that has been linked with mRNA vaccines.
Pfizer said these data will be included in a “near-term submission” for EUA and the companies will continue to accumulate the data needed to file for FDA approval for people ages 5 to 11.
The Pfizer/BioNTech vaccine is currently approved for people age 16 and older, and authorized for use in people ages 12 to 15.
Pfizer said it is expecting trial data for children as young as 6 months “as soon as the fourth quarter of this year.”
“Since July, pediatric cases of COVID-19 have risen by about 240 percent in the U.S. — underscoring the public health need for vaccination. 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,” Albert Bourla, chairman and chief executive officer of Pfizer, said in the statement.
Dr. Scott Gottlieb, a former FDA commissioner and current Pfizer board member, has said a vaccine for children ages 5 to 11 could be available by Halloween.
Acting FDA Commissioner Dr. Janet Woodcock and Dr. Peter Marks, director of FDA’s Center for Biologics Research and Evaluation, said in a statement this month that the agency would review data for a vaccine for younger children “as quickly as possible, likely in a matter of weeks rather than months,” once it was submitted for authorization.
“However, the agency’s ability to review these submissions rapidly will depend in part on the quality and timeliness of the submissions by manufacturers,” they wrote.
Calls for a Covid-19 vaccine for younger children have grown louder in recent months as cases surged among children.
Coronavirus infections have risen “exponentially” among children across the United States, and now account for nearly 29% of all cases reported nationwide, the American Academy of Pediatrics reported last week.
Still, US health officials have emphasized that children are not just small adults, and even those approaching age 12 should not be given the larger vaccine dose available for older people.
“We don’t want children to have adverse effects. Granted, we want them to be able to get vaccinated as quickly as possible, but let’s do it right,” FDA’s Marks said in a fireside chat hosted by the ResearchAmerica Alliance last week.
“There is a difference here because they’re not just getting the same-old, same-old dose as a 12 and up person will. They have to get a reduced dose. And that’s why it’s not a good idea for doctors to take things in their own hands at this point.”