CNN  — 

The US Centers for Disease Control and Prevention updated its recommendations for the Pfizer/BioNTech Covid-19 vaccine booster on Wednesday to include children as young as 12, at least five months after they finish the primary vaccine series.

On Monday, the FDA expanded the emergency use authorization for Pfizer’s Covid-19 vaccine boosters to children ages 12 to 15. The CDC’s Advisory Committee on Immunization Practices (ACIP) voted 13-1 earlier Wednesday in favor of recommending the expanded use of Covid-19 boosters for children in this age group.

The CDC had ​authorized the Pfizer/BioNTech Covid-19 vaccine for use as a booster in ages 16 and 17 in December.

“It is critical that we protect our children and teens from COVID-19 infection and the complications of severe disease,” CDC Director Dr. Rochelle Walensky said in a news release. “Today, I endorsed ACIP’s vote to expand eligibility and strengthen our recommendations for booster doses. We now recommend that all adolescents aged 12-17 years should receive a booster shot 5 months after their primary series. This booster dose will provide optimized protection against COVID-19 and the Omicron variant. I encourage all parents to keep their children up to date with CDC’s COVID-19 vaccine recommendations.”

The ACIP recommendation came after the members heard research on rare cases of myocarditis and pericarditis in young people who have gotten Covid-19 vaccines and noting that many parents are concerned about long-term side effects of vaccines. They also considered that vaccine uptake among 12- to 17-year-olds has slowed recently and weighed the record numbers of Covid-19 cases in children amid a surge of the highly transmissible Omicron variant of the coronavirus.

The CDC signed off Tuesday on shortening the booster interval from six months to five months for people who got the Pfizer/BioNTech vaccine. It has also recommended that moderately or severely immunocompromised 5- to 11-year-olds receive an additional primary dose 28 days after their second shot; only the Pfizer/BioNTech shot is authorized for that age group.

Pfizer’s booster dose contains the same amount of the vaccine as the initial doses: 30 micrograms.

Adolescents ages 12 to 15 became eligible to receive their initial series of the Pfizer/BioNTech Covid-19 vaccine in mid-May, opening vaccinations up to about 17 million additional people.

Now, about half of the 12 to 15 population – about 8.7 million – is fully vaccinated, according to data from the US Centers for Disease Control and Prevention. About 5 million of them have been fully vaccinated for more than five months and are now eligible to receive a booster shot.

Children in this age group represent about 5% of the total US population. They account for about 4% of the fully vaccinated population in the US and about 3% of those eligible to receive a booster shot, according to the latest CDC data.

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In October, the CDC recommended that adults who had completed their initial series of the Pfizer/BioNTech or Moderna vaccine at least six months ago receive a booster shot, along with those who received their initial Johnson & Johnson shot at least two months ago.

Overall, about 71.6 million people in the US are fully vaccinated and boosted against Covid-19. That’s less than half of the nearly 180 million people who are eligible to receive their booster shot and about a fifth of the total US population. And at least 67.5 million people ages 5 and up have not received their first dose of Covid-19 vaccine, according to the latest CDC data.

CNN’s Deidre McPhillips, John Bonifield and Jamie Gumbrecht contributed to this report.
Correction: A previous version of this report misstated the month of October as when Covid-19 vaccine booster doses were recommended for children ages 16 and 17 by the US Centers for Disease Control and Prevention. It has been updated to reflect that the agency recommended Covid-19 booster shots for adults in October.