A Centers for Disease Control and Prevention (CDC) advisory panel on Monday indicated it could take a substantially different approach to booster doses of COVID-19 vaccines than the one proposed by the Biden administration.
Members of the CDC's Advisory Committee on Immunization Practices (ACIP) said the evidence on boosters is not clear and indicated it would likely consider a risk-based approach that would prioritize residents of long-term care facilities and health workers rather than all eligible Americans at once.
COVID-19 vaccines continue to maintain high protection against severe disease, hospitalization and death. While some studies have found some waning of effectiveness against infection, members of the panel said the evidence is not clear enough to justify a booster recommendation.
Vaccine efficacy has ranged between 39 percent and 84 percent, according to several studies.
The panel's vaccine working group said it believes the top priority for a booster dose policy should be preventing severe disease in high-risk people. Preventing mild disease is not recommended and may not even be possible.
Almost all hospitalizations are occurring among the unvaccinated, and panel members emphasized a focus on outreach to the unvaccinated rather than planning to boost the people who are already vaccinated.
Variants are going to continue to emerge over time, but the more people get vaccinated, the less likely those variants will be able to evade protection.
Pfizer and BioNTech are asking federal regulators to approve a third dose as a booster shot for all eligible Americans. A representative from Pfizer said studies on the need for boosters are ongoing, and initial data might not be available until late September or early October.
But the Biden administration has already said boosters will be available beginning the week of Sept. 20. Scientists and public health experts have sharply criticized the announcement, accusing the administration of preempting the evidence.
While officials have emphasized that the plan will not move forward without the ACIP endorsement and official approval from the Food and Drug Administration (FDA), panel members said the announcement has already sparked confusion.
Members of the public are actively seeking out booster doses, and some hospitals have been administering them. But until boosters are approved, providers administering them could be severely penalized for doing so.
Pfizer's representative expressed some concern that if boosters are approved before the clinical data is available, it could negatively impact the trials.
The panel did not vote on recommendations for boosters, but did endorse the full approval of Pfizer and BioNTech's COVID-19 vaccine.
The panel voted 14-0 to recommend the vaccine for people ages 16 and older. The move was essentially a formality, as it comes a week after the FDA granted full approval.
The panel had previously voted in favor of an interim recommendation, before the vaccine was fully approved.
The Pfizer-BioNTech vaccine is still available for children as young as 12 years old under an emergency use authorization.
The FDA approval almost immediately spurred a host of new vaccine requirements among private employers and schools.
ACIP panel members said the endorsement by both the CDC and the FDA should instill even more confidence in the vaccine from people who had been hesitant.
Panel members also said they needed more information about how the vaccine works against the delta variant. The data presented Monday by Pfizer and BioNTech went through only mid-March.