Oct. 26, 2021 — The benefits of Pfizer’s COVID-19 vaccine for children ages 5 to 11 outweigh its risks, according to an independent panel of vaccine experts that advises the FDA.
Seventeen of the 18 members of the Vaccines and Related Biological Products Advisory Committee (VRBPAC) on Tuesday voted to recommend the 10-microgram shot for kids, which is one-third the dose given to adults.
One member, Michael Kurilla, MD, director of the division of clinical innovation at the National Institutes of Health, abstained from voting.
If the FDA follows the recommendation, as it typically does, and issues an Emergency Use Authorization for the vaccine, the shots could be available within days.
After the FDA’s final decision, the CDC’s Advisory Committee on Immunization Practices will meet to make specific recommendations for the vaccine’s use. The CDC committee must stick closely to the conditions for use spelled out in the EUA, so its recommendations are likely to be similar to those made by the FDA. The committee’s next meeting is scheduled for Nov. 2 and 3.
“This is a much tougher one than we had expected going into it,” said committee member Eric Rubin, MD, editor-in-chief of the New England Journal of Medicine, during the committee’s meeting on Tuesday. Ahead of the vote, the committee heard presentations outlining the expected benefits of vaccinating children along with its potential risks.
“Children have been greatly impacted by the pandemic,” said Fiona Havers, MD, a medical officer with the CDC in Atlanta who reviewed the epidemiology of COVID-19 in kids.
In the second year of the pandemic, as more seniors have been vaccinated against the virus, COVID cases have largely shifted from older to younger age groups.
So far, there have been more than 1.9 million COVID-19 cases in children ages 5 through 11 in the U.S. Cases in kids saw a big jump in July and August with summer travel, schools reopening, and the dominance of the Delta variant.
And those are just the cases reported to the CDC. Regular testing of anonymous blood samples collected at sites across the U.S. indicate that 6 times as many kids have had COVID than what is reflected in official counts.
Last winter, blood sample testing showed about 13% of children had antibodies against the virus, suggesting they’d been infected. By this summer, that number had risen to 42%.
That figure clearly made an impression on many members of the committee who asked the FDA’s vaccine reviewers if they had tried to account for immunity from past infections in their modeling. They had not.
Some felt that even with a highly effective vaccine — new data presented by Pfizer showed the children’s dose was 90 % effective at preventing symptomatic infections in kids — caution was warranted as much is still unknown about heart inflammation, a rare side effect of the mRNA vaccines.
The inflammation, which is called myocarditis or pericarditis, has been more common in younger age groups. It usually goes away over time but requires hospital care. It’s not known if myocarditis could have lingering effects for those who have it.
There were no cases of myocarditis seen in Pfizer’s studies of the vaccine in children, and no other serious events were seen.
“We think we have optimized the immune response and minimized our reactions,” said William Gruber, MD, senior vice president of vaccine research and clinical development at Pfizer.
But the studies didn’t include enough participants to pick up rare, but serious adverse events like myocarditis.
“We’re worried about a side effect that we can’t measure yet, but it’s probably real, and we see a benefit that isn’t the same as it is in older age groups,” said Rubin.
Benefits vs. Risks
The FDA modeled the benefits and risks for children under a variety of scenarios. The benefits of the vaccines to children very much depend on the amount of transmission in the community.
When transmission is high, the benefits to children — in terms of infections, hospitalizations, intensive care unit admissions — clearly outweigh the vaccine risks.
But when COVID-19 rates are low in the community, as they were in June, FDA analysts predicted the vaccines might send more children to the hospital for myocarditis than the virus would.
The FDA noted that kids who are hospitalized for myocarditis tend not to be as ill as children with myocarditis.
“If the trends continue the way they are going, the emergency for children is not what we might think it would be. That was my concern,” said James Hildreth, MD, president and CEO at Meharry Medical College in Nashville, TN.
But others warned against complacency.
“Thinking that this is going to be the end of the wave permanently may be a little overly optimistic,” said committee chairman Arnold Monto, MD, a professor of public health and epidemiology at the University of Michigan.
Most COVID-19 cases in children are mild. Only about 1% of kids are hospitalized for their infections, according to CDC data. But the rates of hospitalizations in kids are about 3 times higher for people of color — including Blacks, Hispanics, and Native Americans, as compared to whites and Asian Americans.
Since the start of the pandemic, 94 children ages 5 to 11 have died, making it the eighth leading cause of death for kids this age last year.
More than 5,200 children have had a delayed complication from their infections called Multi-System Inflammatory Syndrome – children, or MIS-C. MIS-C can be severe and require hospital care and can lead to myocarditis, or inflammation of the heart muscle. Children ages 5 to 11 are the age group at greatest risk for this complication.
Kids can also get post-COVID conditions known as long COVID. There’s not a lot of data on how often this happens, though it appears to be less frequent in children than in adults. But a survey in the U.K. found that 7%-8% of kids have symptoms from their infections that last longer than 12 weeks, Havers said. Symptoms that can linger for kids include fatigue, cough, muscle and joint pain, headaches, and insomnia.
More than 1 million children have been impacted by school closures so far this year, and quarantines have had lasting impacts on learning, social development and mental health.
Even though kids aren’t usually COVID superspreaders, they can still pass the infection on to others.
“What is clear is that secondary transmission from children, both to other children and to adults, does occur,” Havers said.
For that reason, they can continue the spread of the virus and give it opportunities to mutate and become more dangerous.
“I really am so grateful that we had this discussion and voted to approve,” said Capt. Amanda Cohn, MD, chief medical officer at the National Center for Immunization and Respiratory Diseases. “I think the benefits in this age group really are super important even if they are lower than for other age groups.”