Should Children Be Vaccinated Against COVID?

John Whyte, MD, MPH; Paul A. Offit, MD


March 11, 2021

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  • Ninety-two percent of COVID-19–related deaths have occurred in adults over 55 years of age; only 0.08% have occurred in people younger than 21 years of age.

  • Data on COVID-19 vaccines and children are minimal. The Moderna and Janssen/Johnson & Johnson trials studied individuals 18 years of age and older. Pfizer included a small subset of children between 16 and 17 years of age.

  • Studies of COVID-19 vaccines in children ages 12-18 are currently underway. The next phase of clinical studies may include children between 6 and 12 years of age. There may not be studies covering children younger than 6, who rarely get COVID-19.

  • We may be able to start vaccinating children ages 12-18 by summer 2021. By fall 2021, the proper vaccine dose may be determined for children between 6 and 12 years of age.

  • Mandatory vaccination for children returning to public schools in 2021 is unlikely. Private schools and private companies may choose to require it.

This transcript has been edited for clarity.

John Whyte, MD, MPH: Welcome, everyone. You're watching Coronavirus in Context. I'm Dr Whyte, chief medical officer at WebMD. Are you going to get your kids vaccinated against COVID? Should kids be vaccinated against COVID?

To help answer these questions and provide some insights, I've asked one of the world's most renowned experts on childhood vaccinations, Dr Paul Offit, to join us. He's the director of the Vaccine Education Center at the Children's Hospital of Philadelphia and a pediatrician at the University of Pennsylvania. Dr Offit, thanks for joining me again.

Paul A. Offit, MD: My pleasure. I thought you were going to say, "I asked one of the world's most renowned experts but I couldn't get them, so instead we've got Dr Offit."

Whyte: "So I got Dr Offit." Let's remind our viewers: How often does COVID occur in kids? And how serious is it?

Offit: First of all, if you look at who dies from this virus, SARS-CoV-2, 92% of the deaths occur in people over 55 years of age. If you look at the population less than 21 years of age, which accounts for 26% of the US population, that population accounts for 0.08% of the deaths. So it is true that children get infected less frequently. When they get infected, they get infected less severely.

Nonetheless, this virus does infect children. The number of children who died this past year of SARS-CoV-2 was roughly the same number that typically die of influenza every year, which is between 150 and 200 children. Children can suffer other problems and a longer-term disease called multisystem inflammatory syndrome in children (MIS-C), which can be disabling. So it's certainly worth preventing this disease in children.

Whyte: Let's talk about this poll we recently did at WebMD, where we asked parents who have children under the age of 16 living at home whether they would vaccinate their kids. And 53% of parents with kids 12-16 said they would have their children vaccinated within a year of a shot being approved; 18% said they definitely wouldn't get their teens inoculated against COVID.

But for parents who have kids under the age of five, 41% said they'd have their kids vaccinated, and 22% said they definitely would not get their kids vaccinated. Does this surprise you at all?

Offit: No, I think it's perfectly reasonable. The studies conducted for the Janssen/Johnson & Johnson and Moderna vaccines included people over 18 years of age, so you have no data for less than 18. The Pfizer studies included children as young as 16 years of age, but that subgroup of 16- to 17-year-olds was not large. It's reasonable to be initially skeptical of this vaccine in children. You want to see the data in children 12-18 years of age (and those studies are being conducted now) to make sure that it's consistently immunogenic and safe in at least thousands of children.

I think about when those studies were done, then I think what you're going to see in studies on 6- to 12-years-olds. I'm not so sure that we're going to see studies in children less than 6 years of age. In any case, based on studies looking at the other two groups (the 12- to 18-year-olds and the 6- to 12-year-olds), I think we can start vaccinating older children by the summer, because I think those studies likely will be finished by then.

Whyte: What do you consider "older children"? Over the age of 12?

Offit: Yes. Children 12-18 years of age.

Whyte: How important are these age cutoffs? And why? We see that in other vaccinations for children, we give vaccines at certain ages. Is it because of their developing immune system? Is it the lack of data? Why do we have these age cutoffs?

Offit: For some children, you want to protect them as infants. You give them vaccines at 2 months, 4 months, 6 months, and 12-15 months of age, because you want to make sure that they're fully immune against the diseases that are likely to cause harm in young children (eg, pneumococcal infection, Haemophilus influenzae type B infection, or Rotavirus infection). For some diseases, you're trying to make sure that they're immune as they enter adolescence — the human papillomavirus vaccine, the meningococcal vaccine are given as part of an adolescent platform. That's really what operationally defines how we give vaccines, when we give vaccines.

Whyte: You're a member of the FDA's Vaccines and Related Biological Products Advisory Committee that gives recommendations for approval. What's going to be different in your reasoning when it comes to vaccinating kids? The acting commissioner of the Food and Drug Administration, Janet Woodcock, often talks about how kids are not mini adults. This is a new technology. Do we have to have different perceptions of safety data when you're balancing risk vs benefit?

You talked early on about how we often don't see deaths and serious disease in children — although they do happen — and then we're weighing them against the risks of side effects as well as a developing immune system. How does your calculation differ at all when you're evaluating this for children vs adults?

Offit: If we're talking about SARS-CoV-2 vaccines, let me take a step back for a second. Normally when the FDA Vaccine Advisory Committee looks at data, it's because a company has submitted a biologics license application and they are asking the FDA to license the product. That's not true with SARS-CoV-2 vaccines. These vaccines are being approved through emergency use authorization (EUA), which is not much different from allowing permission to use an investigational new drug.

Whyte: But in fairness, part of the authorization was that both Pfizer and Moderna have announced that they are going to apply for full licensure.

Offit: Right, but that may be a few years down the line. Let me explain how it came to be that it's through EUA and what people should focus on or not focus on. The reason that it's being done through EUA has nothing to do with the size of the trials. The size of the trials — Moderna's trial of 30,000 or Pfizer's trial of 44,000 or Janssen/Johnson & Johnson's trial of 44,000 — is a typical trial size for an adult or pediatric vaccine, and it really has nothing to do with safety follow-up. The follow-up of safety for 2 months after the last dose is typical for any vaccine. If you look at the serious side effects of vaccines — and vaccines, like all medical products, can have serious side effects — they occur within 6 weeks of a dose. By looking 2 months after the last dose, you were jumping with a net regarding safety.

The issue is efficacy. When Pfizer's and Moderna's trials were approved through EUA, you could say that they were 95% effective for 3 or 4 months. You couldn't say beyond that, and that's the difference. You didn't have 1-3 years of efficacy, nor were you going to. When 400,000 people died last year, you're not going to do a 3- or 4-year trial before you release those vaccines.

So the issue is one of efficacy, and I think we weren't jumping without a net there also. If it's highly effective for 3 or 4 months, I think you can assume it's going to be highly effective for at least a year, if not longer. So, that's what's going to happen. I think the companies, as we get 2-4 years' worth of effectiveness data in the real world, will then come back and try to get a license.

In terms of children, you're not going to see those kinds of efficacy trials. You're not going to see studies of 30,000 or 44,000 children to see whether or not you have a vaccinated group and then see whether the vaccinated group is more likely to be protected against disease than the unvaccinated group, because the disease is not that common in children. You'd have to do a much bigger study than the 30,000- or 40,000-person study to do that. That's not going to happen. Rather, it's going to be a little closer to the influenza vaccine model, where you're going to do essentially phase 1 and phase 2 studies in children, which is to say you're going to make sure you have the right dose and then you're going to give the vaccine to a few thousand children to make sure that it's consistently immunogenic and safe. With that, you would then go to vaccines, which is why it could be as early as the summer for children between 12 and 18 years of age.

Whyte: What about kids between the ages of 7 and 12?

Offit: The 6- to 12-year-old group will follow this initial group, and quickly. By September or October, I think we could know whether or not we have the right dose for the dosing interval for that group as well. I would be surprised if we studied children less than 5 years of age. It's very rare for children that young to get sick for the simple reason that the virus, in order to enter cells, has to attach to cells. The receptor that it uses on the surface of cells to bind, the so-called ACE2 receptor, is not expressed as well in very young children. It's a maturational receptor.

Whyte: It's an issue of efficacy — that's why we wouldn't do it for kids less than 5 — as opposed to issues of safety, or we just don't know?

Offit: The main reason is that it's just extremely unlikely for them to get sick. Now, we may do this. If you look at Janssen/Johnson & Johnson's vaccine (the so-called replication effect of adenovirus 26 vaccine), that vaccine has commercial experience — not for SARS-CoV-2, but for other agents like Ebola virus. That vaccine strategy has been used down to 4 months of age. So at least you have commercial experience with that kind of vaccine.

We'll see how this plays out. Making predictions about this virus and this vaccine is always tricky, because you're always wrong. As we move forward, we're going to see us gradually move down in age to 12 and then down to 6 years of age. We'll see what's happening with the pandemic and what the numbers are in very young children to see whether or not that is a disease worth preventing in very young children.

Whyte: Do you think we'll see mandatory vaccination of kids 12 through 17 returning to school in the fall?

Offit: I certainly would be surprised if we had mandatory vaccination at the state level. It would not be surprising to see it at the private level. Companies could do this, and I think privately owned schools could probably do that. I would be surprised if you saw it in a public school because then you're talking about more state mandates, and I don't see that happening with this vaccine, at least not initially. We struggle with this in our hospital; we're a private institution, and there's a certain percentage of people who don't want to be vaccinated, which is true in all hospitals. Do we want to take that next step and mandate the vaccine? I think we're all struggling with this now.

Whyte: Does it change your mind that it's authorized as opposed to fully licensed?

Offit: I'm not a lawyer; I think that's a legal question. Does it matter whether or not you can mandate something if it's under emergency authorization vs biologics vs a licensed product? At least the people who have weighed in on this so far — ethicists at NYU Langone Health like Art Caplan or lawyers at UC Hastings Law like Dorit Rubinstein Reiss — have led me to believe that even though it is under EUA, you could still mandate this vaccine.

Whyte: Dr Offit, I want to thank you for taking the time today to provide some insights and to tell us where the evidence is in terms of evaluating vaccination for kids.

Offit: Thank you.

Whyte: And thank you for watching. If you have questions about coronavirus, drop us a line. You can email them to as well as post them on social media. Thank you.

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