To your Health! Our kids can’t wait to get vaccinated

This week, my daughters were very excited for Wednesday. It was neither of their birthdays, and that day isn’t a holiday; it wasn’t even a dessert night, so what could there possibly be to look forward to?

Wednesday was the day the Advisory Committee on Immunization Practices (ACIP) was scheduled to vote on whether they recommend the Pfizer/BioNTech vaccine for kids aged 12-15. The ACIP is a group of medical and public health experts whose job is to make sure that vaccines are used safely in the U.S. They’re not part of the government, but their word on vaccines is pretty close to law, as the CDC uses their recommendations to set all nonmilitary vaccination schedules in the country.

The FDA gave the Pfizer/BioNTech vaccine emergency use authorization for this age group on Monday. That made ACIP recommendation the last hurdle the vaccine needed to clear before becoming the first vaccine against COVID-19 available throughout the U.S. for kids under age 16.

How vaccines are assessed for kids

The nice thing about testing vaccines for kids is that the grown-ups always go first. By the time researchers start to look at how a vaccine behaves in children, they already have data not only from the original clinical trials with adults, but also from how the vaccine has performed on adults in the real world (nearly 140 million of them thus far, in the case of Pfizer/BioNTech). That’s why clinical trials for kids don’t need to include as many people—the major safety testing has already been done by adults.

That being said, kids are not simply smaller adults, which is why they get their own sets of trials. The same rules apply: The trials need to prove both safety and benefit. For the 12-15 set, the big safety concerns were immune system overreactions, including allergic and autoimmune responses, neither of which was a significant problem for this vaccine. For the adult trials, the intended benefit was making sure fewer people died or were hospitalized. Since kids are so much less likely to die or be hospitalized for COVID-19, manufacturers used a different metric: They measured the amount of antibodies kids make in response to the vaccines. This told the researchers—and will tell the ACIP—that kids’ immune systems respond adequately to the vaccine.

In terms of dosage, the amount of vaccine a 12- or 15-year-old will get is the same as what I received, which makes sense when you think about it: My older daughter is 3 inches taller than I am and weighs roughly the same as I do (sigh). As the vaccine makers move into testing with younger kids, that dose will likely decrease. Dr. Buddy Creech, associate professor of pediatrics and director of the Vanderbilt Vaccine Research Program, explained the process to ProPublica: “As we go down in age, we give the smallest possible dose of vaccine that we think is reasonable, and then we steadily increase until that point when we get that magic ‘Goldilocks’ level at which it works great and the side effects are tolerable.”

Liz Ruark is the founder of covidsafeschools.org and co-chair of COVID-Safe Schools, Harvard Public Schools’ community COVID-19 screening program. She holds a DVM degree from Tufts Cummings School of Veterinary Medicine.