Many dad and mom within the U.S. have been waiting to hear that the nation’s youngest kids—these beneath 5 years previous—could be vaccinated in opposition to COVID-19. Lastly, on June 15, an skilled panel convened by the U.S. Meals and Drug Administration (FDA) mentioned that two vaccines, made by Pfizer-BioNTech and Moderna, are secure and efficient for youngsters ages 6 months and older.

The FDA’s panel voted unanimously—21-0—that the advantages of Moderna’s vaccine outweigh its dangers for teenagers ages 6 months by 5 years of age. In addition they voted unanimously that the advantages of Pfizer-BioNTech’s vaccine outweigh dangers for teenagers ages 6 months by 4 years.

The FDA normally follows the suggestions of its advisory committee and is thus anticipated to authorize the pictures for emergency use. Assuming it does, the vaccine advisory group of the U.S. Facilities for Illness Management and Prevention (CDC) will assessment the info and resolve whether or not to make a proper advice for vaccination on this age group.

If the CDC recommends the vaccine, kids ages 6 months to five years previous may get their pictures as quickly as subsequent week, changing into the final age group eligible for vaccination in opposition to COVID-19. Whereas charges of COVID-19 on this inhabitants are comparatively low, charges of hospitalization are slowly rising, presumably because of the dominance of the Omicron variant. In response to the latest data from the CDC, greater than 2 million circumstances of COVID-19 have occurred amongst kids 4 years previous or youthful for the reason that begin of the pandemic, resulting in greater than 440 deaths.

Whereas members of the FDA committee extensively felt that oldsters ought to have the ability to vaccinate their younger kids in opposition to COVID-19, some argued it’s vital to maintain the illness’s comparatively modest results on youngsters in perspective. In response, Dr. Arthur Reingold, head of epidemiology on the College of California, Berkeley’s College of Public Well being, famous that youngsters are routinely vaccinated in opposition to ailments that carry low dangers of hospitalization and demise—and COVID-19 ought to be no completely different.

Different committee members mentioned vaccination’s advantages don’t cease at stopping illness. The pictures may additionally reduce kids’ odds of developing complications like Long COVID and supply some freedom to households which have remained largely remoted till their youngest members might be vaccinated.

Pfizer-BioNTech’s pediatric vaccine

The Pfizer-BioNTech vaccine for teenagers ages 6 months to 4 years previous is a three-shot routine, and every dose is one-tenth the dosage given to adults. Kids would obtain two doses three weeks aside, and a 3rd dose a minimum of two months later.

In an organization research involving greater than 4,500 kids, antibody ranges generated by these kids have been in comparison with these produced by vaccinated folks ages 16 to 25 years previous. This allowed researchers to deduce how a lot these antibodies protected in opposition to COVID-19. Within the pediatric group, three-dose vaccine efficacy in opposition to symptomatic illness was 80.4% throughout a time when Omicron was circulating extensively within the U.S.—although that estimate was based mostly on such a small variety of circumstances that it’s tough to attract agency conclusions about how protecting it’s in real-world conditions.

It’s been a protracted street for the Pfizer-BioNTech vaccine. The businesses started submitting their vaccine for FDA authorization on this age group final December, after gathering knowledge on a two-dose course. However these two doses generated comparatively low ranges of immunity, partly as a result of they have been examined whereas Omicron was dominating the U.S. That prompted the FDA and Pfizer-BioNTech to hold off on reviewing that data till the businesses supplied extra info on whether or not including a 3rd dose would enhance ranges of virus-fighting antibodies, and due to this fact immunity, in opposition to COVID-19. The corporate reported these knowledge in Could.

Moderna’s pediatric vaccine

Moderna’s vaccine for youngsters ages 6 months by 5 years previous is given in two pictures, and every dose is one-quarter the dose of that utilized in adults. These immunized with Moderna would get two doses spaced 4 weeks aside.

Moderna examined its two-dose vaccine in additional than 6,300 kids. Amongst these ages 2 to five, the pictures have been about 37% efficient at stopping symptomatic illness when Omicron was prevalent. For teenagers ages 6 months to 2 years, efficacy was round 50% in opposition to symptomatic illness.

The similarities and variations

One of many greatest variations between the 2 vaccines is the variety of pictures: two for Moderna and three for Pfizer-BioNTech.

Pfizer-BioNTech shifted to a three-dose schedule after trial outcomes confirmed that two of their kid-sized doses didn’t immediate a powerful sufficient immune response. In the course of the FDA assembly, Pfizer officers mentioned their aim was to keep away from unintended effects like fevers, which may dissuade dad and mom from getting their youngsters vaccinated.

Whereas the dosages additionally differ between firms, each will give the youngest kids decrease doses than these used for adults and older youngsters, with the intention to greatest stability the protecting advantages in opposition to the potential dangers of unintended effects. These vary from delicate ones similar to fever and swelling on the injection website to extra severe, however rarer, circumstances similar to irritation of the guts tissues and multisystem inflammatory syndrome (MIS-C), a condition that may trigger irritation in lots of components of the physique.

Each vaccines have been comparatively secure and didn’t generate extra opposed results amongst kids than amongst adults, though the committee members paid shut consideration to the danger of myocarditis, an irritation of the guts tissues that has been reported among young adult males ages 16 to 25 years previous. The CDC’s vaccine unintended effects database didn’t reveal the next price of the situation amongst youthful kids.

What occurs subsequent?

If the CDC recommends the vaccines for this youngest age group, dad and mom will possible should make a difficult determination about which shot their kids will obtain. Moderna’s two-dose routine might be extra handy and imply fewer workplace or pharmacy visits, in comparison with Pfizer-BioNTech’s three-dose schedule. It could additionally take a a lot shorter period of time for teenagers to turn into absolutely vaccinated. Then again, Pfizer-BioNTech’s three doses seem to supply increased ranges of virus-fighting antibodies.

Committee member Dr. Paul Offit, director of Kids’s Hospital of Philadelphia’s Vaccine Training Middle, was involved by Pfizer-BioNTech’s “surprisingly poor” vaccine efficacy after two doses. He and different panelists apprehensive that oldsters gained’t understand their kids aren’t effectively protected till after their third pictures—particularly since youngsters in the identical age group solely want two doses of Moderna.

Learn Extra: FDA Recommends the Emergency Authorization of Moderna’s COVID-19 Vaccine for Children Ages 6 to 17

Finally, extra doses might turn into mandatory for all kids, provided that the vaccines presently in use have been designed to focus on the unique SARS-CoV-2 virus. That virus has since been changed by waves of various variants; Omicron, specifically, is better able to evade the immunity produced by the vaccines than previous variants. That’s why the FDA and CDC now advocate that every one adults obtain a minimum of one booster after their preliminary two-dose vaccination with both Pfizer-BioNTech or Moderna’s pictures, with the intention to push waning ranges of virus-fighting antibodies again as much as ranges that may defend in opposition to an infection and extreme illness.

Whereas the committee was not tasked with evaluating the necessity for added doses at this assembly, the identical specialists will convene once more on June 28 to debate boosters and future COVID-19 vaccination plans. They’ll additionally assessment knowledge associated to new vaccines developed to target Omicron particularly.

“I feel Omicron has introduced us to the purpose the place we have to redefine what the first sequence of vaccination in opposition to COVID-19 ought to be,” says Dr. Kristin Moffitt, an infectious illness specialist at Boston Kids’s Hospital (who doesn’t serve on the FDA committee). “We’re in fully uncharted territory and in a really dynamic scenario, for the reason that virus and its evolution is basically what’s driving the bus right here.”

It’s attainable, for instance, that by the autumn, well being officers might have sufficient knowledge from newer, Omicron-specific vaccines to resolve that everybody—together with kids—ought to obtain a minimum of one dose of these up to date vaccines to stay protected in the course of the winter season. That call can even rely on long run knowledge from the continuing pediatric research that each Pfizer-BioNTech and Moderna are persevering with to gather on how lengthy safety in opposition to Omicron lasts with their present vaccine formulations, which in kids have solely been studied for a few months at most. “The query for fogeys is, will the Pfizer-BioNTech vaccine with its three doses defend youngsters all through the autumn and winter in order that they gained’t want one other booster, v youngsters who acquired two doses of Moderna and might have a further dose earlier than the autumn and winter season?” says Dr. Bonnie Maldonado, who chairs the committee on infectious ailments for the American Academy of Pediatrics and is chief of infectious ailments in pediatrics at Stanford College of Medication. “We don’t know the reply to that but. At this level, we will say that each vaccines are secure and efficient in defending kids in opposition to COVID-19 illness, and that oldsters will now have a alternative, which is useful.”

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Write to Jamie Ducharme at jamie.ducharme@time.com.