Americans 12 and older can get a COVID-19 vaccine, but younger children are still waiting.
With many schools across the United States now just weeks from reopening for the fall semester, pharmaceutical companies Pfizer and Moderna are still doing clinical trials to see how coronavirus vaccines work in children under 12 — if they’re safe and what the right dose should be.
Meanwhile, all but four states are seeing an increasing trend in cases, with doctors describing patients who are younger and sicker than what they saw in the winter.
The surge in cases has many parents of children under 12 asking when their little and not-so-little ones can get the vaccine. The answer is that it’s going to be months, if not longer. It’s not as simple as administering available adult doses to younger people.
“I understand parents’ concern in wanting their children to get vaccinated, but we have to make sure we’re doing the best and safest thing for children,” Dr. Chip Walter, a pediatrician at Duke University and an investigator for the Pfizer trials, said.
Vaccine timing
Pfizer’s vaccine study is enrolling more than 4,600 children in three age groups: 5-to-11-year-olds; 2-to-5-year-olds; and babies 6 months up to age 2.
Data for children 5 to 11 could come sometime in September and depending on the findings, the company told CNN it could ask the US Food and Drug Administration to authorize emergency use of the vaccine that same month.
Data for 2-to-5-year-olds could arrive soon after. For the youngest children, Pfizer said it could potentially get data in October or November, and shortly thereafter ask the FDA to authorize emergency use.
Emergency use considerations by the FDA can take several weeks, meaning a vaccine for younger children likely won’t be available until late fall or even next year.
Moderna’s vaccine study is enrolling about 6,700 children ages 6 months to 11 years. It declined to provide a timeline to CNN on when it could potentially have trial data results.
“The companies have said the fall ... I’d be surprised if they can move that quickly, although I suppose it’s possible,” Dr. Peter Hotez, a vaccinologist and dean of the National School of Tropical Medicine at Baylor College of Medicine, said.
“I can’t imagine that we’d be in a position to even consider how to use these vaccines until the very end of the calendar year of 2021, going into the first quarter of 2022,” said Dr. Buddy Creech, a pediatric infectious disease specialist at Vanderbilt University and one of the lead investigators for Moderna’s pediatric COVID- 19 vaccine. “I love that we’re riding the success of how quickly we were able to get a vaccine for adults, but we’ve just got to be patient.”
‘Not just little adults’
A year and a half into the pandemic, parents might wonder why isn’t there a vaccine for younger children yet. After all, some young kids are just as big as older children for whom the vaccine is authorized.
“Boy, have I had this discussion with several parents,” said Dr. William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University and a vaccine adviser to the US Centers for Disease Control and Prevention. “It doesn’t have anything to do with size. It has everything to do with maturity of the immune system, and that doesn’t correlate one-to-one with the size of the child.”
Young children may need different doses. They may need a different number of doses. They may not need as many doses.
“We don’t know for young kids,” Creech said. “Children are not just little adults.”
And children aren’t all the same, either.
“What you may see in a child that’s six months of age may differ from what you see in a child that’s 3 years of age versus a child who’s 8 years of age, or versus an adolescent who’s 13 or 14. So, you really kind of need to take each age separately and evaluate the vaccines,” Walter said.
Creech said finding the “Goldilocks dose” for young children takes time. Give too little and the child may not make enough of an immune response to the coronavirus. Then they’re getting a vaccine with the potential for side effects with little or no benefit.
“We never like to do that. That’s away from goodness,” Creech said.
But give children too much and the balance swings in the other direction.
“You’re getting a good immune response, but you’re unnecessarily triggering things like fever, arm pain, fatigue and fussiness,” he said. “If I get a vaccine and my arm hurts for the day, my wife might make fun of me, but it’s not that big of a deal. I’ll just whine a little bit. But if a two-year-old gets a shot in the thigh, has such severe leg pain that they can’t crawl or walk, well now we’ve got a different issue, and that produces a great deal more anxiety.”
Watching for effects
For kids who may be on the cusp of being eligible, the reason they can’t get the vaccine is also, in part, a bit arbitrary.
“Certainly some children are bigger than others. You might have a really large 10-year-old who’s the size of a 12-year-old where the vaccine’s indicated, but in general we work on recommendations for certain age groups and it’s really best to go by that guidance,” Walter said.
Hotez and Creech agreed.
“Is there something dramatically different between an 11-year-old and a 12-year-old? Probably not. But you’ve got to draw a line somewhere, and historically, the FDA has considered preteens to be different than teenagers from a regulatory standpoint,” Creech said.
“Why was the decision made to do it at 12 instead of 11 or 10 or 14, that I don’t know. I guess you could have moved that goal post either way, probably,” Hotez said.
Another reason the vaccine is moving slowly: the companies want to make sure it doesn’t make children who get COVID-19 sicker, a scenario called immune enhancement.
Hotez said the companies also want to make sure the vaccine doesn’t worsen a rare but serious post-COVID-19 related disease called multisystem inflammatory syndrome in children or MIS-C. In some instances, it has led to neurological abnormalities and deaths.
Risk to children
Although far more rare than in adults, children can suffer, be hospitalized and die from the coronavirus. Plus, this virus does something other viruses that have vaccines, like chickenpox and measles, do not do; it can cause long-term side effects — post-infection phenomena like MIS-C and also long COVID-19, where symptoms can drag on for months.
For now, while the world waits for a vaccine, unvaccinated young children remain vulnerable. “Kids are going to continue to be exposed. Kids are going to continue to transmit, although it seems, at least based on our experience so far in the pandemic, that they may be less efficient at that than adult counterparts,” Creech said.