Why is it taking so long to get a Covid vaccine for kids?

As kids around the US head back to school, there has been disappointing news for parents of children younger than 12. While many health experts had hoped for an early fall approval of a vaccine for young children, two of the nation’s top public health officials said it’s not going to happen.

“I’ve got to be honest, I don’t see the approval for kids 5 to 11 coming much before the end of 2021,” said Dr. Francis Collins, director of the National Institutes of Health, on the NPR program “Morning Edition.”

Dr. Anthony Fauci, the nation’s top infectious disease expert, offered a slightly more hopeful timeline. He told the Today Show on NBC that there was a “reasonable chance” that Covid-19 shots would be available to children younger than 12 by mid- to late fall or early winter. Both Pfizer and Moderna are gathering data on the safety, correct dose and effectiveness of the vaccines in children, he said.

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“The data ultimately will be presented to the FDA to look at for the balance between safety and risk-benefit ratio for the children,” Fauci said. “I hope that process will take place expeditiously.”

It’s not clear if the initial predictions for an early fall vaccine were just overly optimistic, or if officials now think the review process will take longer than expected. The revised timeline comes after the Food and Drug Administration in July asked Pfizer and Moderna to expand the size of their clinical trials for younger children to make sure they could detect potentially rare side effects.

But Pfizer said the number of children it planned to enroll was already large enough to meet the FDA recommendations, and it had always planned to submit its data in September. A company spokesperson said that it takes time to recruit and enroll children in a clinical trial. Pfizer is enrolling up to 4,500 children, including 3,000 in the 5 to 11 age group, and another 1,500 children younger than 5.

The news that a kid’s vaccine won’t be approved quickly is no doubt upsetting to many parents, who were counting on an early fall vaccine to keep their children safer in classrooms. Given the urgency of getting kids vaccinated, I asked vaccine expert Dr. Paul Offit why it’s taking so long. Not only is Offit on the FDA’s vaccine advisory committee, he has also gone through the agency’s authorization process, as the co-inventor of a rotavirus vaccine for infants, which was approved in 2006.

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Offit recalls that the trial data for the rotavirus vaccine was delivered in a truck. “If you took (the reports) and stacked one on top of the other, it exceeded the height of the Sears Tower,” Offit said. “It’s a lot of information.”

While Offit understands that parents are frustrated with the delay in approving a Covid vaccine for young children, it also should be reassuring that the FDA is taking the time necessary to review the vaccine data, he said. The agency doesn’t just rely on the company’s summary of the data. Agency officials look at individual reports from every single child, reviewing the most mundane details of any side effects, blood tests and other data collected during the trial. The data on children are complicated by the fact that different doses are being studied.

“They don’t want to miss anything, because the No. 1 thing is safety,” Offit said. “You’re giving a vaccine or placebo to thousands of children as a predictor of what’s about to be given to millions of children. I know it seems like it should be faster, but it’s a long process.”

While parents will have to wait a little longer before young children can be vaccinated, studies show that schools have not been a major cause of Covid spreading events, particularly when a number of prevention measures are in place. A combination of precautions — masking indoors, keeping students at least 3 feet apart in classrooms, keeping students in separate cohorts or “pods,” encouraging hand washing and regular testing, and quarantining — have been effective. While many of those studies occurred before the delta variant became dominant, they also happened when most teachers, staff and parents were unvaccinated, so public health experts are hopeful that the same precautions will work well this fall.

The overall news is reassuring when it comes to children and the risks of serious complications from Covid-19. Compared to adults, children diagnosed with Covid-19 are more likely to have mild symptoms or none at all. Children are also far less likely to develop severe illness, be hospitalized or die from the disease. In rare cases, some children infected with Covid may develop a serious inflammatory syndrome, but that has been documented in only about 0.1% of pediatric cases. While the loss of even one child is devastating, deaths among children from Covid-19 are rare. Since the start of the pandemic, the CDC has documented 454 deaths in the 18 or younger age group, accounting for 0.07% of the total 623,984 deaths in all age groups.

Parents can minimize a child’s risk by getting all eligible family members vaccinated. Take precautions daily to avoid crowds, wear a mask and encourage your child to wear a mask at school.