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The Next Steps for Pfizer’s COVID-19 Booster Doses

CDC panel weighs who should be eligible for a third dose

September 23, 2021

The Centers for Disease Control and Prevention’s (CDC) advisory panel met today to discuss who should receive a booster dose of Pfizer-BioNTech’s COVID-19 vaccine.

The meeting of the Advisory Committee on Immunization Practices (ACIP) is one of the final steps before the distribution of booster doses of the Pfizer-BioNTech vaccine can begin. Late Thursday, CDC Director Rochelle Walensky, MD, MPH, signed off on the committee's recommendations and added guidance that boosters should be available to health care workers and others who have jobs that put them at increased risk of exposure to the virus.

ACIP members voted to recommend a Pfizer-BioNTech booster dose for:

  • People 65 and older, as well as residents in long-term care facilities
  • People between 50–64 with underlying medical conditions
  • People between 18–49 with underlying medical conditions, based on individual benefit and risk

The boosters would be given at least six months after the completion of the initial two-dose series.

The panel voted 9–6 against offering boosters to a broader group of Americans 18–64 who are in an occupational or institutional setting where the burden of COVID-19 infection and risk of transmission are high. The vote came after a lengthy discussion about the available evidence to recommend boosters more broadly. CDC officials said they expected additional review and discussion about this group of individuals during upcoming meetings.

On Wednesday, the U.S. Food and Drug Administration amended its emergency use authorization (EUA) to allow for booster doses of the Pfizer-BioNTech vaccine for people 65 and older, as well as other high-risk groups. The EUA only applies to Pfizer-BioNTech’s COVID-19 vaccine.

“These data are not perfect, yet collectively they form a picture for us, and they are what we have in this moment to make a decision about the next stage in this pandemic,” Dr. Walensky said at the start of the meeting.

The ACIP two-day panel concluded a review of the following topics:

  • Evaluating efficacy:  The Pfizer-BioNTech vaccine’s protection against infection appears to wane months after initial vaccination across age groups, but it continues to provide strong protection against severe cases and hospitalizations. Among people 65 and older, the protection against infection is declining faster than for the rest of the population
  • Risk analysis:  The CDC’s advisory group considered the benefits of a booster dose of the Pfizer-BioNtech vaccine—such as preventable hospitalizations—against the risk for rare cases of myocarditis from a third dose. The greatest benefit was among people 65 and older
  • Equity:  COVID-19 vaccination rates and cases vary by socioeconomic and sociodemographic status. Vaccine effectiveness does not vary by race and ethnicity
  • Mix-and-match:  The CDC’s advisory panel said there was not enough available data to recommend people mix COVID-19 vaccines (Pfizer-BioNTech, Moderna, Johnson & Johnson), but this topic would be reviewed at a later date

During the meeting, public health officials said the booster shots are only part of the COVID-19 vaccine campaign. The rollout of booster doses will occur alongside the larger effort to vaccinate the remaining people who haven’t received the vaccine.

Hospitalization rates are ten to 22 times higher in unvaccinated adults when compared to vaccinated adults, said Sara Oliver, MD, MSPH, a member of the CDC's Epidemic Intelligence Service. 

HAP will continue to monitor COVID-19 public health developments about booster doses and provide updates to members.  Additional information about the ACIP meeting is available online.