CDC's Advisory Committee on Immunization Practices (ACIP) on Wednesday voted 14-0 to recommend authorizing Pfizer and BioNTech's Covid-19 vaccine for use in children ages 12 to 15.

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CDC Director Rochelle Walensky shortly afterward adopted the committee's recommendation, marking the first time that a Covid-19 vaccine has been made available for adolescents in the United States.

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Data was presented to ACIP regarding a clinical trial of 2,260 children ages 12 to 15 that assessed the effectiveness of Pfizer's vaccine.

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In the trial, 1,131 participants received the vaccine and 1,129 received a saline placebo. The trial found the vaccine was 100% effective at preventing Covid-19 among the participants, with no participants in the vaccine group developing Covid-19 compared with 18 in the placebo group. The trial also found that the adolescents developed even higher levels of antibodies post-vaccination than adults did.

Minor side effects were common, with 91% of participants experiencing injection site pain, fatigue, and/or a headache. Almost 20% reported a fever after their second dose, with one child experiencing a fever as high as 104.7 degrees Fahrenheit. A small number of those who received the vaccine also experienced lymphadenopathy, or a swelling of lymph nodes, that was determined to have been caused by the vaccine.

What happens next

According to President Joe Biden, 15,000 pharmacies nationwide are prepared to start administering the vaccine to adolescents as soon as Thursday. He added that school-based clinics and family health centers will also be administering shots.

"We're also going to be getting these vaccines to pediatricians and family doctors, so parents and children can talk to their doctors who they trust about getting the vaccination, and they'll be able to do it at that office," Biden said.

Other sites already vaccinating adults should also be able to start vaccinating adolescents, Janet Woodcock, acting commissioner of FDA, said. "All those sites can simply extend down to the younger age group," she said.

However, parent hesitancy may present a significant roadblock in getting adolescents vaccinated, data shows. A poll from the Kaiser Family Foundation (KFF) found that more than 40% of parents of adolescents said they won't get their child vaccinated or would only do so if it was required by school.

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That survey also found that just 30% of parents with at least one child between the ages of 12 and 15 said they will get their child vaccinated as soon as possible, and 26% said they will wait to see how the vaccine is working.

Separately, data presented by CDC officials to ACIP noted that just 46% to 60% of parents said they want to get their children vaccinated.

What this means for the Covid-19 epidemic

With ACIP's approval, a new segment of the U.S. population is now eligible to receive a Covid-19 vaccine. According to the New York Times, there are almost 17 million children between the ages of 12 and 15 in the United States.

And as more adults have been vaccinated, adolescents have made up a larger share of Covid-19 cases. Data presented by CDC to ACIP said that children ages 12 to 17 accounted for 9% of all cases in April.

CDC data also shows that, while children are at a lower risk of developing Covid-19 and especially severe Covid-19 than older adults, an estimated 22.2 million children ages 5 to 17 have contracted Covid-19, and, between Jan. 1 and April 30, 127 have died. Sarah Oliver, an epidemiologist at CDC, noted that the 127 deaths would have ranked Covid-19 in the top 10 causes of death among children in 2019.

Oliver also said more children between the ages of 12 and 17 have been hospitalized with Covid-19 than were hospitalized with H1N1 during the 2009 pandemic or have been hospitalized with influenza over the past three years.

Meanwhile, Walensky said ACIP's recommendation makes it more likely that children will return to full time in-person schooling in the fall.

"I think we should be five days a week everybody present in school in the fall," she said. "I think we will be in a place in this pandemic that we will be able to do that. I think we should all be leaning in."

And as for younger children, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and chief medical advisor for the White House, said he believes that authorization could come later this year.

"We think by the time we get to the end of this year we will have enough information to vaccinate children of any age," he said (Branswell, STAT News, 5/12; Owemohle/Foley, Politico, 5/12; Mandavilli, New York Times, 5/12; Lovelace, CNBC, 5/12; Hopkins/McKay, Wall Street Journal, 5/12; Choi, Associated Press, 5/12; Sun/Nirappil, Washington Post, 5/12; Holcombe, CNN, 5/13; Hamel et al., Kaiser Family Foundation survey, 5/6).