When members of the Centers for Disease Control and Prevention’s independent Advisory Committee on Immunization Practices met, on Wednesday, to weigh the use of the Pfizer-BioNTech COVID-19 vaccine in children aged twelve to fifteen, they went through something of a public-health catechism. Was the vaccine safe for these children? Yes, judging from clinical trials, with more than two thousand children, and also from the experience of the millions of people sixteen and older who have received the vaccine worldwide. And was the vaccine effective in these children? Yes, in the trial, the children appeared to be almost completely protected from COVID-19. The Food and Drug Administration had extended the emergency-use authorization for the Pfizer vaccine two days earlier, based on the same data. The committee’s vote—which was unanimous in favor of lowering the eligible age to twelve—was the next step; Rochelle Walensky, the head of the C.D.C., quickly accepted the recommendation, saying in a statement, “This official CDC action opens vaccination to approximately 17 million adolescents in the United States.” The statement includes a number that families can text to find an appointment: 438829, or GETVAX.

None of the thousand and five children who completed the clinical trial and were given the vaccine got COVID-19; sixteen of nine hundred and seventy-eight children who completed the trial and received the placebo did. (None died.) A comparison with a slightly older group—sixteen- to twenty-five-year-olds—found that, if anything, the younger group had a more robust immune defense. The twelve- to fifteen-year-olds were asked to keep “e-diaries,” in which they recorded certain symptoms they experienced that could be reactions to the vaccine. Those reactions, when they occurred, were generally minor and dissipated quickly, and were similar to those in the sixteen- to twenty-five-year-old group (a few more had a fever; slightly fewer had muscle pain). No “severe adverse events” were linked to the vaccine in the younger group.

Another question put before the committee was this: “Is COVID-19 disease among adolescents aged 12-15 years of public health importance?” It is one of those obvious questions that can yield a rich conversation. The short answer, backed up by the data presented on Wednesday, is yes, very much so. We are in a pandemic from which, as much as one might wish it, children have never been exempt. The closer they are to adolescence, the truer that appears to be the case. By the end of April, some five hundred and eighty thousand COVID-19 deaths had been logged in the United States; a hundred and twenty-seven of them were among children aged twelve to seventeen. (There are indications of what may be a different, more tragic trend regarding the toll among children in the COVID-19 surges in India and Brazil, but whether that is because of variants that are increasingly prevalent in those countries or a breakdown of the hospital systems there—people are “dying because they can’t get oxygen,” as Dhruv Khullar writes of the situation in India—or simply a reflection of the horrendously high number of patients over all needs to be clarified.) Still, because deaths of any kind among children in this age group are fairly rare, COVID-19 ranks in the top ten causes of death in this group.

Children who survive COVID-19 may also be seriously affected by it. Among the data put before the committee was the number of cases of multi-inflammatory syndrome in children (3,742) and the cumulative number of COVID-related hospitalizations among twelve- to seventeen-year-olds (just under fifty per hundred thousand). The children who were hospitalized appear to be disproportionately Black and Latino, and to have underlying conditions. It is hard to know how many cases of COVID-19 there have been in children, because they frequently have no symptoms, but a million and a half cases have been logged in the U.S. among twelve- to seventeen-year-olds—likely a fraction of the true number. There are growing concerns about “long COVID” in children—lingering or recurring effects that may follow even mild cases. Also, because so many adults have been vaccinated, children make up a growing share of cases—now eighteen per cent. If the pandemic is to end, children have to come into focus.

These numbers are, in absolute terms, still very small, and each can provoke arguments, including angry conflicts about the safety of opening schools—children can also be harmed by their closure. There are few absolutes here. It is sometimes argued that children are not the “primary drivers” of COVID’s spread, which, even on its own terms, leaves open the question of secondary drivers. There is no doubt that children can infect others, although that is more common with older children. Having the vaccine means that children no longer need to live with the anxiety that they may unwittingly spread the virus to a more vulnerable relative or friend—a true liberation for many of them. Among the charts that the committee looked at was one indicating that adults living in a household in which children attended school full time in person were more likely to report having COVID-19 symptoms or a positive test, and that the numbers were highest for those living with high-schoolers. However, the full study that the data were taken from, which was published by Science, also asked about more than a dozen mitigation measures—from teacher or student mask mandates to extra space between desks, outdoor instruction, and symptom checks—and found that the more measures there were in a child’s school, the less likely it was that adult family members fell ill. For families whose children attended schools that adopted seven items from the mitigation menu, the effect entirely disappeared. The problem is that epidemiological questions get tangled up with political and fiscal ones.

A promise of the authorization of the vaccine for twelve- to fifteen-year-olds—and for younger children, which will no doubt follow—is that it will break the school-opening logjam. The availability of vaccines for teachers has already begun to shift the balance in the debate. On Thursday, when Randi Weingarten, the president of the American Federation of Teachers, called for all schools to reopen in the fall full time in person, she said that nearly ninety per cent of the nation’s teachers are vaccinated or are willing to be. One of the areas that she said needed work, however, was in making sure that children get a vaccine.

The number of parents who are hesitant about getting their children a vaccine is high. One of the grimmest charts that the committee looked at summed up surveys showing that only forty-six to sixty per cent of parents intended to have their children vaccinated. The next step will be in figuring out how to reach and win over those who don’t. A survey found that some parents would be most comfortable with their children getting the vaccine in a pediatrician’s office. Others would be willing to have their children vaccinated if schools required it—and there will no doubt be fights over such requirements, which will play out differently in various parts of the country. (Pfizer has applied for a full, rather than emergency-use, authorization, which would make it easier for schools to require the shot.) A simple move like lowering the age for the vaccine can, again, open up a range of other questions. How can it be done equitably? What about the rest of the world? Should appeals against vaccine hesitancy be directed at young people or their parents? But one thing is clear: for public health, and for children themselves, it’s an important moment.

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