A panel of independent advisors to the Food and Drug Administration is recommending that the agency issue an emergency use authorization for the Pfizer-BioNTech vaccine in children ages 5 to 11 years old. The vote was 17 in favor and one abstention.
The FDA panel accepted Pfizer’s data indicating the vaccine is safe and 90.7% effective in preventing COVID-19 infections in this age group.
The agency typically goes along with the advice of its expert panels, though it isn’t bound to do so. It will issue a decision within the next several days. If the FDA authorizes the vaccine for younger children, as seems likely, another panel of experts advising the Centers for Disease Control and Prevention would make recommendations on its use for younger children next week.
The vaccine provides a broad defense against COVID-19 and “effectively neutralized the delta variant” in this age group, said Dr. William Gruber, senior vice president of vaccine clinical research and development at Pfizer, speaking during the committee hearing.
A dose of Pfizer for young children contains one-third the amount of active ingredient as the adult dose. Children would receive a second dose 21 days or more after their first shot.
Gruber said the dose size was chosen to “strike the right balance” between providing strong immunity and limiting side effects. He said that the observed adverse effects seen in the company’s studies “did not suggest any safety concerns.” An FDA review supported that conclusion.
Children 5-11 years of age have accounted for approximately 9% of reported COVID-19 cases in the U.S. overall and currently account for approximately 40% of all pediatric COVID-19 cases, says Dr. Doran Fink, clinical deputy director of the division of vaccines and related products for the FDA. Currently, the case rate in children 5-11 years of age is “near the highest” of any age group, he says.
Fink and others testifying at the meeting acknowledged that serious effects of infection, including long COVID-19, hospitalizations, and deaths are less frequent in children than in adults, but argue that there are significant numbers of serious illness in young children that warrant concern. Unvaccinated children with COVID-19 can develop a serious complication called multisystem inflammatory syndrome or MIS-C, and also an inflammation of the heart muscle called myocarditis.
Myocarditis has also been observed as a side effect after Pfizer and Moderna shots. In studies of young children submitted by Pfizer to the FDA, there were no cases of myocarditis observed. But Dr. Leslie Ball, a medical officer at the FDA, said that the studies seeking emergency use authorization were not large enough to necessarily pick up an uncommon side effect like myocarditis.
Overall, the incidence of serious side effects in Pfizer’s studies was less than 2 in 1000, Ball said, and all were unrelated to the vaccine.
Less serious side effects that occurred more often included swollen lymph nodes in a few children and the reactions commonly seen with many vaccines, such as pain at the injection site, fatigue and headache, she said.
Several people opposed to the authorization testified during a public comment period, citing cases of vaccine-related side effects, and arguing that the benefits do not outweigh the risks. They maintained that children don’t get sick as often as adults and that the possible risks of side effects outweigh whatever benefits might accrue.
During the scientific presentations and discussion, the cases of myocarditis that have been related to the vaccine got the most attention. Myocarditis occurs naturally after infections with other viruses and it has been seen after vaccination with the two mRNA vaccines, Pfizer and Moderna vaccines.
The committee was concerned with a higher frequency of myocarditis seen in adolescents who’ve gotten the Pfizer vaccine.
“It’s always nerve-wracking, I think, when you are asked to make a decision for millions based only on studies of a few thousand children,” said committee member Paul Offit, a pediatrician at Children’s Hospital of Philadelphia. But Offit said he was “reassured” that the number of myocarditis cases in children 5-11 years old was lower than older adolescents and younger adults.
Dr. Amanda Cohn, a medical officer with the CDC, also a voting member of the FDA committee, said that the number of children in the Pfizer studies is similar to the number that has been used to approve other childhood vaccines.
“I don’t want to minimize the risk,” Cohn told the committee during a debate over the vote. “At this moment, based on the totality of the evidence, the benefits do outweigh the risk,” she said.
“We have incredible safety systems in place to monitor for the potential for myocarditis in this age group and we can respond quickly,” she added. “To me, the question is pretty clear. We don’t want children to be dying of COVID, even if it is far fewer children than adults, and we don’t want them in the ICU.”
Pediatric cardiologist Matthew Oster, who works with the CDC’s Center on Birth Defects and Developmental Disabilities, presented an extensive review of what is known about this side effect. He said both historical studies of myocarditis before the pandemic, during the pandemic and after vaccination show that myocarditis is most common in children and adults between 16 and 29 and much more likely to happen in males than females. Most children and adolescents recover from myocarditis.
The committee’s recommendation comes as more than 1.9 million cases have been reported in children ages 5-11, with approximately 8,300 children hospitalized to date, according to the Centers for Disease Control and Prevention. About one-third of these hospitalized children required treatment in the ICU. The rate of hospitalization is three times higher in children of color than white children.
Many in the public health community see an urgent need to get vaccinations started in young school-age children, in part to address the unequal effect of the pandemic on people of color. Dr. Fiona Havens of the CDC presented data to the FDA committee showing that between August and early October, COVID outbreaks have closed 272 school districts, affecting 2,074 schools. Some 1,069,116 students and 68,718 teachers were affected. She said there was a disproportionate impact on children of color.
Havens further said 5,217 children had gotten MIS-C, a serious complication of COVID-19. The median age for MIS-C is 9 years and 39% of cases occur in 6-11 year olds; more than 60% of those cases were in children of color. The complication causes serious inflammation of several organ systems in the body.
As for long-term effects of the infection in children, Havens said that data are lacking on how often children develop long-term COVID, though one study from the U.K. found 7% to 8% of children had symptoms more than 12 weeks after the initial diagnosis.
The FDA modeling several scenarios to estimate the effect of vaccinating children. One showed that vaccinating 1 million 5-11 year olds would prevent 58,000 infections, 241 hospitalizations and one death. In that same 1 million, there might be anywhere from 22 to 106 cases of myocarditis associated with the vaccine. Most would be expected to fully recover.
An advisor with the FDA, Hong Yang said that in most scenarios, the benefits of vaccinating the 5-11 year old population “clearly outweigh” the small risk of myocarditis.
However, when the level of COVID-19 transmission in the community is low, there may be more hospital admissions due to myocarditis than COVID-19, Wang said. At the present time, with high levels of COVID-19 transmission in most areas of the country, the overall benefits of vaccination “may still outweigh the risks” she concludes.
Dr. James Hildreth, a committee member and president of Meharry Medical College in Nashville, Tenn., ultimately voted to authorize the vaccine, but said it was a “challenging decision.”
Hildreth said he was surprised to learn that as many as 40% of children in this age group have been infected with the coronavirus so far, which he says could mean that as many as 30 million children may have some form of immunity already. And he said he was also “disappointed in the [low] number of minorities” included in the Pfizer studies, “because they bear the brunt of disease and hospitalizations.”
“It just seems to me in some ways we’re vaccinating children to protect the adults,” Hildreth said. “It should be the other way around.” The focus, he said, should be on adults getting vaccinated to protect the children.
He said he voted yes “because I want to make sure the children who really need the vaccine — primarily the black and brown children in our country — get the vaccine.”
Pfizer’s Gruber said that other advantages of early childhood vaccination would include possibly reduced virus transmission, improved herd immunity and increased in-person learning, supporting child development.
But Ball said that in the FDA’s analysis, the agency was unable to determine if there was an impact of vaccination on the spread of the virus. Gruber said that given that the antibody response was similar to that seen in adults, and that high antibody levels had slowed transmission in older populations, “it would be reasonable to expect” that the same would be true for children aged 5-11.
The formulation being used for this pediatric dose is not only a lower dose, the company is using a different substance to maintain stability so that the vaccine can be stored for up to 10 weeks in a refrigerator. The doses for those 12 and up must be kept frozen until the day of use and have a more limited shelf life.
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