26 Oct. 2021 – The benefits of Pfizer’s COVID-19 vaccine for children aged 5 to 11 outweigh the risks, according to an independent panel of vaccine experts advising the FDA.
Seventeen of the 18 members of the Advisory Committee on Vaccines and Related Biological Products (VRBPAC) voted on Tuesday to recommend the 10-microgram injection for children, which is one-third of the dose given to adults.
One member, Michael Kurilla, managing director, director of the division of clinical innovation at the National Institutes of Health, abstained.
If the FDA follows the recommendation, as usual, and issues an Emergency Use Authorization for the vaccine, the shots may be available within days.
“This is a much harder one than we expected to go into,” committee member Eric Rubin, managing director, editor and head of the New England Journal of Medicine, said during the committee’s meeting Tuesday. Prior to the vote, the committee heard presentations outlining the expected benefits of vaccinating children along with the potential risks.
“Children were greatly affected by the pandemic, ”Says Fiona Havers, MD, a medical officer at the CDC in Atlanta who reviewed the epidemiology of COVID-19 in children.
In the second year of the pandemic, as more seniors were vaccinated against the virus, COVID cases largely shifted from older to younger age groups.
To date, there have been more than 1.9 million COVID-19 cases in children between the ages of 5 and 11 in the U.S. Cases in children have seen a big jump in July and August with summer travel, schools reopening and the dominance of the Delta variant.
And these are just the cases that have been reported to the CDC. Regular testing of anonymous blood samples collected at sites across the U.S. indicates that 6 times as many children had COVID as reflected in official counts.
Last winter, blood samples showed that about 13% of children had antibodies to the virus, indicating that they were infected. By this summer, that number had risen to 42%.
This figure clearly made an impression on many members of the committee who asked the FDA’s vaccine reviewers if they had tried immunity of previous infections in their modeling. They did not.
Some felt that even with a highly effective vaccine – new data presented by Pfizer showed that the children’s dose was 90% effective in preventing symptomatic infections in children – caution was warranted, as many are still unknown about heart infection, a rare side effect of the mRNA vaccines.
The inflammation, which is called myocarditis or pericarditis, is more common in younger age groups. It usually goes away over time, but requires hospital care. It is not known whether myocarditis can have long-term effects for those who experience it.
No cases of myocarditis were 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 kept our responses to a minimum,” said William Gruber, MD, senior vice president of vaccine research and clinical development at Pfizer.
However, the studies did not include enough participants to pick up rare but serious adverse events such as myocarditis.
“We are concerned about a side effect that we cannot yet measure, but it is probably real, and we are seeing a benefit that is not the same as it is in older age groups,” Rubin said.
Benefits vs. Risks
The FDA has modeled the benefits and risks for children under a variety of scenarios. The benefits of the vaccines for children depend a lot on the amount of transmission in the community.
When the transmission is high, the benefits to children – in terms of infections, hospitalizations, ICU admissions – clearly outweigh the risks.
But when COVID-19 rates were low in the community, as in June, FDA analysts predicted that the vaccines could send more children to myocarditis for the hospital than the virus would do.
The FDA noted that children admitted to the hospital for myocarditis tend not to be as sick as children with myocarditis.
“If the trends continue as they are, the emergency for children is not what we would think it would be. That was my concern, ”said James Hildreth, MD, president and CEO at Meharry Medical College in Nashville, TN.
But others have warned against complacency.
“Thinking it’s going to be the end of the wave permanently can be a little too optimistic,” says committee chairman Arnold Monto, MD, a professor of public health and epidemiology at the University of Michigan.
The majority of COVID-19 cases in children are mild. Only about 1% of children are hospitalized for their infections, according to CDC data. But the rates of hospitalizations in children are about 3 times higher for people of color – including Blacks, Hispanics and Native Americans, compared to whites and Asian Americans.
Since the start of the pandemic, 94 children aged 5 to 11 have died, making it the 8thste main cause of death for children this age last year.
More than 5,200 children have developed a delayed complication of their infections called Multi-System Inflammatory Syndrome – children, or MIS-C. MIS-C can be severe and require hospitalization and can lead to myocarditis, or inflammation of the heart muscle. Children between the ages of 5 and 11 are the age group at greatest risk for this complication.
Children can also get post-COVID conditions known as lank COVID. There is not much data on how often this happens, although it seems to occur less frequently in children than in adults. But a survey in the UK found that 7-8% of children have symptoms of their infections that last longer than 12 weeks, Havers said. Symptoms that may persist for children include fatigue, Coughmuscle and joint pain, headaches, and insomnia.
More than 1 million children have been affected by school closures so far this year, and quarantines have had a lasting impact on learning, social development and mental health.
Although children are not usually COVID super-distributors, they can still transmit the infection to others.
“What is clear is that secondary transmission from children, both to other children and adults, does occur,” Havers said.
For this reason, they can continue to spread the virus and give it opportunities to mutate and become more dangerous.
“I’m really so grateful we had this discussion and voted to approve it,” 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 are really very important, even if it is lower than for other age groups.”