on its vaccine recommendations.
The Advisory Committee on Immunization Practices, or ACIP, recommended that all adults be eligible for a third dose of a Pfizer or Moderna mRNA vaccine, at least 6 months after their second dose.
They also strengthened a recommendation that everyone over the age of 50 should get a third dose, whether or not they have an underlying health condition that may increase their risk from a COVID-19 infection.
The committee voted 11 to 0 in favor of both policies.
CDC Director Rochelle Walensky, MD, must now sign off on both policies, which she is expected to do.
More than 70 million adults are now eligible for booster shots in the United States, but only about 31 million people have received one. About half of those who have been boosted are over the age of 65.
In a recent survey, the Kaiser Family Foundation found that about 4 in 10 younger adults said they were unsure if they qualified for a booster.
Under the current policy, boosters are recommended for everyone age 65 and older. But people who are younger than age 65 are eligible for boosters if they have an underlying health condition or live or work in a high-risk situation—something individuals have to determine on their own. Experts said that shading of the policy had created confusion that was holding people back.
Nirav Shah, MD, JD, president of the Association of State and Territorial Health Officials, noted that public health officials have been swamped with calls from people who are trying to figure out if they are eligible to get a booster dose.
He said that in a call the evening of Nov. 18 with state health departments, “There was not a single state that voiced opposition to this move,” he told the ACIP.
Dr. Shah said that the current guidelines were well intentioned, but “in pursuit of precision, they create confusion.”
“Our concern is that eligible individuals are not receiving boosters right now as a result of this confusion,” he said.
The committee based its decision on the results of a new study of boosters in Pfizer vaccine recipients, as well as reassuring safety information that’s being collected through the CDC and FDA’s monitoring systems.
Pfizer presented the early results from a study of 10,000 people who had all received two doses of its vaccine. Half of the study participants received a third shot, or booster. The other half got a placebo.
The study is ongoing, but so far, six of the people in the booster group have gotten a COVID-19 infection with symptoms compared to 123 people who got COVID-19 in the placebo group, making boosters 95% effective at keeping people from getting sick. Most people in the study had gotten their original doses about 10 months earlier. They’ve been followed for about 10 weeks since their booster. Importantly, there were no study participants hospitalized for COVID-19 infections in either the placebo or booster group, indicating that the first two doses were still very effective at preventing severe outcomes from infection.
The majority of side effects after a third Pfizer dose were mild and temporary. Side effects like sore arms, swelling, fever, headache, and fatigue were more common in the booster group — affecting about 1 in 4 people who got a third shot. Vaccination side effects were less common after boosters than have been seen after the second dose of the vaccine.
Some cases of myocarditis and pericarditis have been reported after people received vaccine boosters, but the risk for this heart inflammation appears to be extremely low, about two cases for every million doses given. There were 54 cases of myocarditis reported so far to the Vaccine Adverse Event Reporting System, or VAERS. So far, only 12 have met the case definition and are considered related to vaccination. Most of the reported cases are still being studied.