(WASHINGTON) — Federal advisers on Friday voted 18-0 in favor of recommending Pfizer booster shots for anyone over 65 or anyone who is at high risk of severe disease from COVID-19. However, the panel declined to recommend boosters for all Americans as young as 16 who took the Pfizer vaccine more than six months ago.

If the Food and Drug Administrations agrees with the plan, which is likely, it’s possible that booster shots would roll out as early as next week to these populations. The Centers for Disease Control and Prevention would weigh in first though with more specific recommendations on who exactly should take the third shots.

Members of the FDA’s Vaccines and Related Biological Products Advisory Committee scrutinized new data from Israel and questioned whether boosters are really necessary, particularly among younger populations.

The largest sticking point was the lack of data on the effect boosters could have on young people, particularly because 16- and 17-year-olds weren’t included in the trial. Myocarditis, a heart inflammation condition, occurred mostly in young men, though very rarely, after their second mRNA dose, so members wanted to see more data on the effects of a third shot.

While many Americans have already opted for third shots, with doctors allowing them as an “off-label” practice, it’s up to federal regulators to decide how the vaccines are labeled and administered.

The debate has become unusually charged, in part because of White House involvement. President Joe Biden said he would only act on rolling out boosters if the FDA and CDC agreed. But his public pronouncement that the rollout would begin as early as Monday suggested the decision was a foregone conclusion, leading to accusations by some scientists that the Biden administration was pressuring independent regulators.

Following FDA approval, the CDC will determine who exactly should get a booster. After that CDC recommendation is made, booster shots would be available through any of the nation’s 40,000 pharmacies, doctors offices and other sites already offering the Pfizer vaccine.

The CDC has said vaccines still offer extraordinary protection against hospitalization and death, with more than 90% of patients hospitalized with COVID-19 being unvaccinated. At Friday’s FDA briefing, a CDC official said vaccine effectiveness against hospitalization in adults age 75 and older remained at about 88% through July.

But there were other signs that immunity waned with time.

A new Israeli study published in the New England Journal of Medicine found 11.3-fold lower rates of infection and 19.5-fold lower rates of severe COVID-19 among people older than 60 who got a booster dose. Also, an Israel Ministry of Health analysis estimated approximately 10-fold improved protection against infection and severe COVID-19 among people who got a booster.

Sharon Alroy-Preis, head of public health services at Israel’s Health Ministry, said Israel became concerned when it saw cases of fully vaccinated residents infecting other members of their households and – at times — winding up hospitalized.

“We definitely see that cases that are vaccinated — doubly vaccinated — that are no longer fresh” six months from their second dose, Alroy-Preis said. These vaccinated cases “are infecting other people. It’s obviously less than non vaccinated. But we’re seeing that, especially in their household.”

ABC News’ Sony Salzman contributed to this report.

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