In his practice as a pediatrician, Dr. Sean O’Leary gets a lot of calls from worried parents. And, lately, one kind of call has begun to stand out.
“The parents I hear from are the ones who are reaching out to me desperately because they want their kids to have a COVID vaccine,” he said.
O’Leary is an infectious disease specialist at Children’s Hospital Colorado and also a professor at the University of Colorado School of Medicine. But he is perhaps best known as an international expert on childhood immunization, a role that sees him involved in an advisory capacity with the federal vaccine approval process.
So parents call him, thinking he may have some inside knowledge on when vaccines will be available for the only age group not yet eligible for vaccination against COVID-19: Kids under the age of 5.
It’s been a long wait for Colorado’s youngest residents to get a vaccine — now 26 months into the pandemic and 17 months since the first adults began receiving COVID vaccines. But plenty of signs are finally starting to signal a change.
“The good news is that we will almost certainly have at least one vaccine and maybe two ready pretty soon here,” O’Leary said.
The bad news: There’s probably still a couple more months of waiting.
The long road to a vaccine for young kids
Two companies are aiming for approval of vaccines for children under the age of 5: Moderna and Pfizer. Both companies are using reduced-dosage versions of their adult COVID vaccines. And both are expected to soon come up for federal approval.
Moderna last week formally asked the federal government to approve its two-dose vaccine for kids ages 6 months through 5 years. The Food and Drug Administration set dates in June to discuss the request.
Those meetings could potentially also see discussion about the Pfizer vaccine, O’Leary said. The company is expected soon to announce the results of testing on a third dose of its vaccine for kids 6 months through 4 years. (Pfizer’s vaccine already has approval for everyone ages 5 and up, while Moderna’s is approved only for adults, ages 18 and older.)
But it hasn’t been an easy road to get to this point.
Pfizer earlier this year released data on a two-dose regimen of its vaccine for young kids and subsequently requested federal approval. But, while the numbers looked good for kids in the 6 months to 2 years age range, they were underwhelming for kids older than that, and the federal government opted to hold off until the results of Pfizer’s tests on a third dose came in.
“It’s not something you would want to rush without having all the data,” O’Leary said.
Mounting frustration among some parents
While caution is appreciated, it hasn’t been enough to stave off rising frustration among some parents — including the state’s most powerful parent, Gov. Jared Polis.
Late last month, Polis — whose children are old enough to be vaccinated — sent a letter to President Joe Biden urging him to speed up approval for COVID vaccines for kids under age 5. Polis wrote in the letter that it is “immoral to wait any longer” on approving the Pfizer vaccine for children ages 6 months to 2 years and he urged Biden not to wait to approve the Pfizer and Moderna vaccines together.
Polis wrote that federal regulators should approve the vaccine applications “as soon as they are ready and the data is sufficient.”
“Colorado parents have been told, over and over again, that COVID-19 vaccines are on the horizon for their children,” Polis wrote. “They deserve the choice of vaccinating their children and peace of mind. The lack of transparency and opaque communication from vaccine manufacturers and the FDA is eroding trust.”
O’Leary said he understands the frustration.
“I wish we had a vaccine for these kids six months ago,” he said.
Why is it taking so long?
To O’Leary, the lengthy timeline for approval isn’t really a surprise.
He said it’s entirely normal for regulators to need several weeks to review data on vaccine safety and efficacy, especially when it is a “rolling submission” like what Moderna is doing, meaning data are submitted over time instead of all at once. And pediatric vaccines are always subject to extra scrutiny because regulators want to be especially sure they are safe.
In his letter, Polis expressed concerns about federal regulators waiting until they have data from both Pfizer and Moderna before they make a decision. But O’Leary said he doesn’t think that’s what’s happening. Rather, he said it appears it’s just going to work out that both will be ready to review at the same time.
It also makes sense to review the two vaccines together, if possible, O’Leary said. What if one works better than another for this age group? Wouldn’t you want that to be part of the federal government’s recommendations?
“Honestly I don’t see it particularly as a delay,” he said.
It’s also important to keep this frustration in perspective.
According to the Kaiser Family Foundation’s most recent poll on parents’ attitudes toward vaccination, only 18% of parents of kids under 5 intend to get their children vaccinated as soon as they possibly can. A far bigger chunk — 38% — say they want to wait and see. And another 38% say they either won’t vaccinate their young kids or will only do so if required.
O’Leary believes it is important that young kids get vaccinated against COVID — they can suffer serious consequences from a coronavirus infection. But he said the delay in approving the vaccines likely doesn’t come at a very high cost to children.
Statistically, kids under 5 are much less likely than adults to get seriously ill or be hospitalized if infected. O’Leary put the risk on par with other daily activities that also carry some potential for peril, like riding in a car at the risk of an accident.
“The risk to young kids for hospitalization from COVID is in line with some of the infectious diseases we’ve dealt with for decades, like flu or RSV,” he said.
Recalibrating expectations for efficacy
When the federal government does approve the vaccines for young children and releases all the clinical trial data, O’Leary said parents will need to adjust their focus and expectations.
The headline-grabbing numbers when vaccines were approved for adults were for efficacy — 90%+ protection from symptomatic COVID. But efficacy at preventing infection has lagged in kids under 5 for both Moderna’s and Pfizer’s vaccines. Moderna’s vaccine, for instance, was only about 50% effective at preventing infection in kids 6 months to 2 years, and only 37% effective in kids 2 through 5.
The vaccines were tested against different versions of the virus, though, O’Leary said. The vaccines for adults were formulated and tested during waves of the original COVID variants, while the vaccines for kids were tested during the days of omicron, which is better at causing breakthrough infections. In a news release, Moderna said its pediatric efficacy rates were on par with the protection its vaccine provided adults against omicron.
O’Leary also said efficacy against infection doesn’t matter as much now as it once did.
“We want to be thinking about what is the protection against severe outcomes,” he said.
Moderna reported no hospitalizations for COVID among children in its clinical trial.
Watching out for rare side effects
No major side effects have been reported so far from the clinical trials in young kids — about the most serious issue reported was a temporary fever. But the trials have been small, at least compared to the studies for the adult vaccines, which enrolled tens of thousands of participants.
O’Leary said it’s unlikely that there is a significant unknown side effect out there lurking just for small children. Hundreds of millions of doses of the Pfizer and Moderna vaccines have now been administered across the globe.
One concerning rare side effect seen in older kids and young adults, a heart condition called myocarditis, is not likely to be as prevalent in young kids, O’Leary said. Cases of myocarditis following COVID vaccination have generally tracked with the overall population curve of myocarditis cases — the condition is most common in teens and young adults, in general.
But he stressed that the nation’s vaccine monitoring system is in place to catch and address any unexpected effects.
“We have a pretty good idea of the side effect profile,” O’Leary said. “It would be surprising if we were to discover something different in these kids.”
CORRECTION: This story was updated at 2:45 p.m. on Friday, May 6, 2022, to correct the risk of COVID infection and hospitalization for kids under the age of 5. They are less likely than adults to be infected or to be hospitalized, but are not the age group with the least risk for hospitalization, according to CDC data.