On June 25-26, the newly reconstituted  Advisory Committee on Immunization Practices (ACIP) held its first public meeting. The meeting offered insight into future directions for both the committee and the immunization programs that are guided by the committee’s recommendations.

Background

ACIP is a chartered federal advisory committee responsible for making recommendations on the safe and effective use of vaccines. The Committee makes these recommendations to the Centers for Disease Control and Prevention (CDC), and if adopted by the CDC Director and published in the respective Immunization Schedule, these recommendations enable Americans to access vaccines at no cost across most insurance programs.

The ACIP is formally chartered under the Federal Advisory Committee Act (FACA, 1972), which ensures that federal advisory committees operate with open and transparent procedures, maintain public records of proceedings and recommendations to facilitate transparency and objectivity, and hold regular and publicly announced meetings. The committee meets at least three times per year, in February, June, and October. Three weeks in advance of the scheduled June meeting, Secretary of Health and Human Services Robert F. Kennedy Jr announced  that he would remove all 17 sitting members of the committee, noting that 13 members were appointed in 2024 under the Biden administration and “a clean sweep [was] necessary to reestablish public confidence in vaccine science.” Two days later, Sec. Kennedy announced the names of eight new voting members on the social media platform, X (formerly Twitter), one of whom withdrew before the start of the June meeting, citing a review of his financial holdings and leaving the committee with seven sitting members.

ACIP Is the Bedrock of the US Vaccine Policy and Access System

In the sixty years since its establishment, the ACIP has emerged as the cornerstone of US vaccine policy and access systems. Using a rigorous review process that assesses vaccine product safety, efficacy, cost-effectiveness, and programmatic fit, ACIP issues evidence-based recommendations on immunization use, and its recommendations form the foundation for pediatric and adult immunization schedules. These schedules not only guide clinical practice but also trigger first-dollar coverage across most insurance programs.

Federal legislation has incrementally grown to require first-dollar coverage of ACIP-recommended vaccines for more insurance groups (Figure 1). This began with the Omnibus Budget Reconciliation Act in 1993, which tied inclusion in the Vaccines for Children Program to an ACIP resolution. In 2010, the Affordable Care Act requires commercial payers to cover all immunizations that have “in effect a recommendation” from the ACIP and further requires Medicaid expansion programs to cover ACIP-recommended products. These two pieces of legislation tied first-dollar coverage of vaccines for over two-thirds of the American population to ACIP recommendations. The remaining gaps in patient cost-sharing requirements were closed in 2022 with the passage of the Inflation Reduction Act, which eliminated all cost sharing for adult vaccines recommended by ACIP under Medicare Part D, and mandated that traditional Medicaid and CHIP plans cover all approved vaccines recommended by ACIP along with their administration without cost sharing. For more detailed information on US vaccine coverage requirements, see Avalere’s guidebook here.

Figure 1: Evolution of Immunization Coverage Requirements

RSV: Respiratory Syncytial Virus: VFC: Vaccines for Children

In addition to the direct impact ACIP recommendations have on insurance coverage and patient access, the Committee’s decisions also have an indirect impact on state immunization policies, provider counseling behavior, and quality reporting programs (see Figure 2).

State public health departments often rely on ACIP recommendations to drive public health outreach campaigns as well as to shape school and occupational vaccination requirements. ACIP guidance is further embedded in state immunization information systems, which track vaccine administration, and may also be configured for integration with provider electronic health records using the CDC’s clinical decision support for immunization tools.

ACIP recommendations also impact provider scope of practice and quality measurement. State legislators or boards of pharmacy often adapt local pharmacist and pharmacy technician authority to administer vaccination to reflect ACIP recommendations. Quality reporting programs (e.g., childhood immunization status and adult immunization status measures) incorporate adherence to ACIP schedules as performance indicators for providers and health plans.

In essence, ACIP recommendations shape which products are offered in US immunization programs, which patient populations can receive them at no cost, and how immunizations are tracked to assess risk of vaccine-preventable disease outbreaks.

Figure 2: Direct and Indirect Impacts of ACIP Recommendations

VICP: Vaccine Injury Compensation Program

The Committee Is Poised to Revisit the Pediatric Immunization Schedule

In addition to the seven new voting members who were introduced at this week’s meeting, there was also an announcement of two new ACIP work groups, which will add to the extant product-specific work groups and the traditional work group focused on reviewing and updating the child/adolescent and adult immunization schedules on an annual basis.

The first new work group will examine the cumulative effect of the childhood vaccine schedule. The second new work group will review products which have not been subject to review in more than seven years – an extant requirement per ACIP Policies and Procedures which has not been consistently observed. Combined, these work groups signal the reformulated committee’s intention to review previously-established schedules and potentially revise them following new evaluations.

The June meeting initiated this process with discussions on the use of thimerosal-containing influenza vaccines and the use of the measles, mumps, rubella, and varicella (MMRV) vaccine in children. After a presentation on the risks associated with thimerosal the committee voted five-to-one (one abstention) to eliminate the use of thimerosal-containing influenza vaccines. This discussion diverged from the ACIP’s traditional process, which has historically been guided by a structured review of the evidence across several clinical and programmatic domains using a framework called the ‘Evidence to Recommendation’ (EtR) framework.

Following the thimerosal discussion, the new chair, Dr. Martin Kulldorff, presented on the risk of febrile seizures associated with the MMRV vaccine and introduced recommendation language to eliminate MMRV as an option for vaccination in children under 47 months of age. This recommendation will be voted on at a subsequent meeting. It is unclear whether a dedicated WG will be established to support this review or whether it will fall under the remit of one of the newly established work groups.

Neither vote will significantly impact current immunization practices given the low utilization of both thimerosal-containing influenza vaccines and MMRV vaccines in children under four years of age. Still, these discussions may foreshadow additional re-evaluation of other recommendations, likely beginning with the pediatric immunization schedule which has been a major focus area for CDC and HHS leadership.

Real-world Impacts of New or Revised Recommendations Remain Uncertain

ACIP recommendations typically fall into one of three categories: routine recommendations, which are recommended for standard use in a broad population; risk-based recommendations, which are tailored for specific populations that may be at higher risk due to age, medical conditions, or occupation; and shared clinical decision making (SCDM) recommendations, which are designed for situations where a vaccine may benefit some but not all individuals in a given cohort. In the case of SCDM recommendations, the decision to vaccinate should be made jointly between the patient and the provider. All three recommendation types determine coverage requirements across insurance programs.

For patient populations no longer included in the scope of a given ACIP recommendation, payers may continue to voluntarily provide coverage and would be free to apply utilization management requirements—apractice that is not permitted for ACIP-recommended immunizations. For patient populations that are not covered by the scope of an ACIP recommendation, payers may rely on internal product review committees to determine coverage or they may turn to relevant medical societies to inform their coverage protocols. Additionally, while ACIP recommendations establish the minimum coverage requirement for state Medicaid programs, they are free to offer broader coverage.  As payer coverage policies evolve, vaccine access may vary across geographies, patient populations, and insurance programs. .

Conclusion

The current climate surrounding the ACIP is marked by considerable uncertainty, and further developments are likely to occur ahead of the next meeting in the fall. Further agency changes, such as the appointment and Senate confirmation of a CDC Director, could also shift the activities and objectives of the ACIP and the CDC staff who support the ACIP’s research efforts.

Further, given early withdrawals in participation from newly nominated members, additional membership could be solicited and approved in advance of other 2025 meetings.  Additionally, several recommendations from the April meeting remain unadopted and recommendations for other seasonally administered vaccines, like COVID-19, have not yet been voted on, raising questions about whether those recommendations may be revisited in future meetings. In the interim, payers, providers, and industry stakeholders will be monitoring the situation closely for any shifts in evidentiary standards or substantive revisions of existing recommendations.