Five Big Questions About COVID Vaccines for Kids

With FDA authorization for a kid-size COVID vaccine pending, a pediatrician and infectious-disease expert weighs in on what’s next.

children in masks gathered at a New York elementary school
Michael Loccisano / Getty

Some good news finally—finally—appears to be on the horizon for roughly 28 million of the United States’ youngest residents. On the heels of an advisory meeting convened yesterday, the FDA is likely on the cusp of green-lighting a kid-size dose of Pfizer’s COVID-19 vaccine for Americans ages 5 to 11, a move that’s been months in the making.

After the agency’s expected emergency authorization, Pfizer’s formulation will need a recommendation from CDC Director Rochelle Walensky, who’s expected to weigh in next week, after her own advisory committee holds a vote. But the nation is ready: Already, 15 million pediatric doses of Pfizer’s vaccine—which will be administered at a third of the amount doled out to adults—have become available for states to order in advance.

Yesterday’s discussions were tense, understandably so. These immunizations will protect both the kids who get them and the people they mingle with, and they represent one of the few big levers the government has left to pull in the fight against the coronavirus. But as age eligibility for COVID-19 vaccines continues to drop, the risk-benefit calculations get tougher, and more emotional. This age group has been much less likely than others to come down with serious cases of COVID-19. Stacked up alongside that relative resilience are two rare but serious vaccine side effects: myocarditis and pericarditis, or inflammation of the heart and its surrounding tissue, which have appeared more commonly in boys and young men who have received mRNA-based COVID-19 vaccines. Most of the cases have been relatively minor—notedly less severe, for instance, than the heart inflammation that can follow a SARS-CoV-2 infection—but the phenomenon remains poorly understood.

The FDA’s own analysis of the (somewhat limited) data on this age group, presented at yesterday’s meeting, came out in favor of giving pediatric shots the official okay. COVID, after all, is now one of the top 10 causes of death among children ages 5 to 11; the disease has also hit Black, Latino, and Native kids especially hard. But a side effect that’s “less risky than COVID” could still be cause for concern. Maybe the vaccine should be given only to a subset of kids, some committee members argued—those who have medical conditions that up their chances of getting seriously sick, for instance. Still, the panel gave a near-unanimous thumbs-up to the vaccine, with one member abstaining.

Now comes the hard part: actually getting inoculations into little arms, by no means a slam dunk. As shots become available, just in advance of the holidays, parents will have to opt their children in to receive them—two more jabs, on top of the recommended seasonal flu shot, that potentially come with side effects and may confer protection of debated durability. Adopting any new health intervention requires a gamble, but this one might feel especially fraught. There’s still a lot we don’t know about COVID-19 in the youngest among us, and the vaccines we’re using to shield them.

To help make sense of what’s next, I caught up with Sallie Permar, the chair of pediatrics at Weill Cornell Medicine and pediatrician in chief at New York–Presbyterian Hospital in New York. Our interview has been lightly edited for length and clarity.

Katherine J. Wu: The FDA is probably on track to authorize this vaccine within the next couple of days—before the CDC’s advisory panel, ACIP, meets next week. What’s the greatest impact this could have on the pandemic overall, assuming we successfully convince parents to sign their kids up for shots?

Sallie Permar: To me, the most important thing is that this vaccine takes three new diseases that we’re dealing with in children, and seeing consistently in our health systems, and makes them vaccine-preventable. The first is severe COVID-19, the respiratory disease that’s more rare in kids, but still happens, especially in our adolescent populations and those with high risk. The second is MIS-C, an [inflammatory] condition that happens in one in every 3,000 or so infections in children, [and is most common] in the 5-to-11-year age group. And the third is long COVID, which children continue to suffer for months after, due to persistent symptoms.

The second biggest benefit would be about transmission. Children can be protected by masks, and they probably transmit less often [than adults]. But children can definitely be part of the transmission chain, especially when it comes to households, and even in settings where precautions are being used.

Vaccinating our children will make it so we can recapture school as we once knew it, with kids picking who they want to sit [with] at their lunch table, or being able to face any direction in the classroom, and not a certain distance away from their neighbor—maybe even thinking about whether kids can safely go back to school without masks. Masks might still be a good idea when everybody’s indoors and has runny noses during the winter. But we’ll be able to walk back a lot of the restrictions that have been in place. We can’t even think about that until we get high [vaccine] coverage in our children.

Wu: That sounds wonderful, but an authorized vaccine doesn’t guarantee an administered vaccine. You’re a practicing pediatrician—what’s been your sense of how parents will receive this news?

Permar: I foresee a lot of my time in the next few weeks being devoted to [navigating] that. Parents want to make the best decision for their children. And they want to make a very careful decision, and they want to consider all of the information that’s available. It is scary to think about: If I choose a vaccination and my child is one that has a rare side effect, how am I going to feel about that? That’s definitely going through parents’ minds.

The chance that your child will have a severe COVID infection is rare; the chance that your child will have MIS-C is also pretty rare. Not a lot of people know someone who’s had a child in the hospital with COVID. But what’s even more rare is the chance that there will be an ill effect from the vaccine. We have to educate about those numbers.

Not vaccinating is still a risk, and it’s a higher risk than giving your child a vaccine. In fact, we don’t even know if myocarditis is going to be a concern [in 5-to-11-year-olds]. There were no cases in that age group in [Pfizer’s efficacy trial]. Myocarditis tends to be more common in older children. So taking what we know, in this younger age group, it’s postulated to be less of a concern. And let me just say, I am so thrilled that there has been all of this work that went into identifying an age-specific dose for this population. We want to achieve the immune response needed for protection, with the smallest dose to reduce side effects. That is what we should be doing for every new vaccine going forward.

One question I get often is “I have an 11-year-old who’s turning 12 in three weeks. Should I wait? The higher dose seems better, right?” First of all, don’t wait for the bigger dose—you never know when COVID will enter your life or your child’s life. Secondly, I think I would actually prefer to get them the lower dose. Pediatric immune systems are more well set up to respond to low doses. They may even achieve a better response. We’ve been studying this in the HIV-vaccine world for several years now. A lower dose in a young age group can achieve a better immune response than even a higher dose. I wouldn’t be surprised if we go to an even lower dose with the youngest age groups.

Wu: That sounds really promising. At the same time, though, we don’t have certainty on side effects yet. Pfizer’s trial was small—too small to pick up a reliable signal of myocarditis, so we’ll need to wait to see what happens when the vaccine rolls out to a much larger group. How should parents weigh the risk of a rare side effect against the risk of COVID-19, which is less common among young kids? And should certain children be prioritized for the vaccine, and others advised to wait?

Permar: If you were playing the numbers and reading the data, you would give your child the vaccine every time. [The alternative] would be taking an unknown risk, and making that the reason you’re not going to protect your child against a known risk that you know how to protect against.

Severe infections have been unusual in children, which has been a blessing. But we have no idea what predicts who is going to have MIS-C. Hopefully, we’ll go forward and identify those things. We have some idea of who might be at risk for severe respiratory COVID—older adolescents, [kids with] obesity, diabetes. But there are also children where we don’t know what made them at risk for infection. We see this in flu, too. Totally healthy children just get a very severe illness. We see totally healthy children just get very sick, and you can’t put your finger on it.

Wu: Will vaccinating kids feel less urgent if transmission rates plummet?

Permar: One thing we know will happen is that there will be new variants of this virus. If the pattern holds true, they will be more transmissible. They may even be vaccine resistant. What drove a lot of parents of adolescents to finally get vaccines [this summer] was that the case numbers rose immensely with the more transmissible Delta variant. That’s great, but it was also too late. It takes five to six weeks [from the first dose] to get fully immune. So we have to anticipate there will be other variants that we will deal with. My hope is we get this last segment highly vaccinated, and that will maybe slow down the variants. But we should not count out a new variant, and we have to anticipate that.

Wu: Getting vaccines down to young kids took a very long time, and we still haven’t reached the under-5 crowd. What can we learn from this? Did it have to be this way?

Permar: We’ve got to do this differently in the future. It is a travesty that we sent kids back to school without this vaccine available to them, while adults were benefiting from vaccine immunity, going to restaurants with our vaccine cards. We should not leave children to the very last. Maybe in the future, we can start testing age groups in parallel.