Pfizer COVID vaccine appears safe, effective in kids ages 5-11 — but questions remain

The Pfizer-BioNTech coronavirus vaccine appears to be safe and effective in children between 5 and 11 years old, according to the companies, with a dose that’s a third of the amount given to teens and adults.

The two shots given 21 days apart also brought on side effects that were “generally comparable” to those experienced by 16- to 25-year-olds, Pfizer officials said in a statement released Monday. The companies plan on submitting their data to the U.S. Food and Drug Administration and other regulatory agencies before the winter.

The announcement lifts a weight that has been sitting on some parents’ shoulders as pediatric COVID-19 cases skyrocket across the country. Since July, coronavirus infections among kids have risen by about 240%, according to Pfizer officials.

“Over the past nine months, hundreds of millions of people ages 12 and older from around the world have received our COVID-19 vaccine,” Albert Bourla, chairman and CEO of Pfizer said in the statement. “We are eager to extend the protection afforded by the vaccine to this younger population, subject to regulatory authorization, especially as we track the spread of the delta variant and the substantial threat it poses to children.”

Beyond stating that its vaccine is safe and effective, Pfizer officials did not share specific data on efficacy or side effects among the 2,268 children included in the clinical trial. This means we don’t know how well the shots protected kids from coronavirus infection or hospitalization, which leaves some experts hesitant to express their opinions on the results.

“It’s frustrating that we’re in an age of science by press release. Until we look at the data, I can’t comment on this, other than to say: We need a vaccine for children,” Dr Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia and member of an FDA advisory committee, told The Washington Post.

Pfizer said the “safety profile and immunogenicity data” of its vaccine in a lower dose in kids between 5 and 11 years old are “consistent” with those observed in older people at a higher dose. “Immunogenicity data” refers to antibody levels produced after vaccination.

But without revealing more specific numbers or percentages, like it did in March for kids ages 12-15, the company is implying the vaccines will offer similar protection for younger children as it does for older kids and adults. Scientists also don’t know if higher antibody levels equal stronger or more protection against COVID-19.

It’s a kind of scientific assumption called “immune-bridging,” according to Dr. Jeremy Faust, an emergency medicine doctor at Brigham and Women’s Hospital in Massachusetts.

“While the lack of direct clinical information is disappointing, it’s not entirely surprising. This trial mainly sought to evaluate safety (the frequency of adverse events) and antibody levels. Given how unusual — and yet not unheard of — serious Covid-19 illnesses are in children, the study was correctly conceived,” Faust wrote in a Facebook bulletin he runs called Inside Medicine.

“So while the data we were given today are ‘surrogate measures,’ the results taught us something important: the lowest considered dose generated similarly robust antibody levels, implying a protective effect was provided. This makes having waited for these data, rather than pressing ahead without safety or immunologic information, wise,” Faust continued.

Pfizer did not mention reports of serious side effects, including myocarditis — inflammation of the heart muscle — which has been affecting younger recipients, mostly male, after Pfizer or Moderna COVID-19 vaccination. However, a Pfizer spokesperson confirmed with CNN there were no cases of myocarditis in its small clinical trial, and that more specific data will be available “in a near-term submission.”

Pfizer also did not mention how the highly contagious delta variant may have affected its vaccine’s efficacy in clinical trials among kids.

Pfizer and BioNTech plan on announcing their data on children between 2 and 5 years old and 6 months to 2 years of age by the end of the year.

The vaccine is currently available for people ages 16 and older under the FDA approved name “Comirnaty.” The shot is also available under an emergency use authorization for kids between 12 and 15 years old and as a third dose for people ages 12 and older who have weakened immune systems.

Last week, an FDA advisory committee voted in favor of a booster shot of the Pfizer COVID-19 vaccine for vaccinated people ages 65 and older and anyone at increased risk for severe COVID-19. The FDA still has to formally authorize third doses for the specific groups. A separate recommendation from a committee within the Centers for Disease Control and Prevention is expected next week when it meets to discuss booster shots.

More than 181.3 million Americans are fully vaccinated against COVID-19 as of Sept. 19, a CDC tracker shows, about 55% of the total population. Of the total, more than 99 million have received the Pfizer vaccine.