The Advisory Committee on Immunization Practice at 60: Lessons Learned in a Time of Vaccine Innovation and Evolution

This year the Advisory Committee on Immunization Practices (ACIP) celebrates its 60^th anniversary. Established in 1964 to advise the HHS Surgeon General and the Communicable Disease Center (as the Centers for Disease Control and Prevention was then known) on vaccine policy and practice, the ACIP began its work at a time when assuring access to vaccines had emerged as a public health policy matter of national importance. At the time, five FDA-approved vaccines were on the market—influenza, polio, smallpox, measles, and a diphtheria, tetanus, and pertussis (DTP) combination vaccine. Funding for population-based vaccination came through limited federal and state grants to public health agencies since, with the soon-to-be exception of children on Medicaid as part of its 1967 early and periodic screening, diagnosis, and treatment (EPSDT) benefit, vaccinations were not considered an insurable service but rather a public health undertaking to prevent the spread of pediatric infections and disease outbreaks. Vaccine costs also were modest: administering the pediatric schedule (smallpox and DTP) to children in the 1950s cost less than $1, a sum that increased to roughly $116 by 1987. The American public collectively embraced immunization.

Sixty years later, the climate is radically different. Today 108 FDA-approved vaccines are on the market, and vaccine technology has started to shift from prevention of infectious disease into the realm of treatment. The concept of immunization itself has expanded to include new technologies, such as monoclonal antibodies, that act similarly to vaccines and have the power to more quickly and effectively prevent the onset of disease. Lifesaving vaccine technologies in response to a global pandemic have emerged at unprecedented speed. The cost of the complete routine immunization schedule for a child from birth to 18 months can now approach $3,000, based on public or private sector access and use of single versus combination vaccines. For adults, 15 vaccines are now recommended for use based on age and risk factors. Over 175 million privately insured Americans and more than 115 million publicly insured beneficiaries (Medicare, Medicaid, Veterans Affairs) have coverage of routine immunizations free-of-charge, and as a result of national health reforms that began with the 1993 Vaccines for Children (VFC) Program, ACIP recommendations adopted by the CDC director have the force of law as a coverage standard. Vaccine use has become exponentially more complex, occurring at a time when vaccine skepticism is at an all-time high.

The evolution of the ACIP and vaccine policy is a microcosm of the story of US health policy more generally, a reflection of vast change over six decades in health care technology, practice, financing, as well as shifting attitudes and sentiment toward medical care. The ACIP has endured throughout, its role and impact only growing in view of the fact that its recommendations now determine insurance coverage standards population-wide.

Two significant, related developments have produced the modern ACIP: 1) the expanded role of immunizations as a health care intervention; and 2) corresponding changes in the ACIP’s responsibilities, structure, role, and deliberation process that have, in turn, changed how recommendations are developed and translated into policy. These changes have heightened the attention given to how ACIP operates. Originally consisting of eight physicians and researchers specializing in virology, immunology, and epidemiology, the ACIP has grown to be able to include up to 20 individuals with a broader range of skills in real-world medical and public health practice along with expertise in the science of vaccinology, vaccine safety and efficacy, vaccine implementation, and health behavior. One position is reserved for a consumer representative knowledgeable in the social aspects of immunization. Reflecting modern sensibilities on financial conflicts, membership is barred to individuals with a financial interest in vaccines.

Rigorous membership requirements carry implications for the size of the qualified member pool and has led to a substantial number of vacancies at any given time, potentially undermining the ACIP’s ability to achieve the quorum needed to ensure timely review of approved products. Under its charter, the ACIP has flexibility to temporarily designate and swear in up to eight ex officio members and grant them authority as voting members for quorum. Temporary membership can solve immediate deliberation and approval problems. However, this jury-rigged solution carries broader implications for the workability and sustainability of the membership model, given the considerable workload ACIP members and CDC staff carry. The ACIP’s workload challenges will only grow as the number, types, and use of immunizations and vaccine-like products increase, raising further questions regarding membership and staffing sufficiency. What once was a scientific advisory body now plays a legally consequential role in health care standard-setting, and yet the ACIP remains small in structure and limited in capacity.

Legislation directly linking ACIP recommendations to insurance coverage has led to a shift in its deliberation and recommendation development process in response to insurer concerns regarding what payers viewed as an insufficiently rigorous decision-making process. To assuage this criticism and reaffirm its commitment to evidence-based decision-making, in 2010, the ACIP adopted a methodology known as the Grading of Recommendations, Assessment, Development and Evaluation (GRADE), followed by its 2018 adoption of the Evidence to Recommendation (EtR) framework to aid decision-making. Together the frameworks aim to improve how the ACIP’s decision-making responds to a public health problem, addresses safety and efficacy concerns, and considers vaccination benefit and risks along with implementation factors such as acceptability, equity, and resource use.

While GRADE and EtR have improved decision-making, no process can guarantee consistency, clarity, and objectivity. As a result, even these improved procedures have been met with skepticism on the part of some manufacturers, clinicians, and consumers. Furthermore, it remains unclear how well the modernized methodology will work for novel products: recent deliberations have shown confusion, especially among members without expertise in cost-effectiveness economic modeling. How this relatively rigid process affects the ACIP’s ability to effectively deliberate regarding more intangible yet equally important factors, such as health equity, also has emerged as a matter of concern.

The problems that can arise in a highly-structured deliberative process have surfaced in the context of public health emergencies such as COVID-19 and mpox, which demanded a fast, nimble response by ACIP that these methodologies generally do not permit, all while trying to maintain public confidence in their recommendations. Furthermore, the ACIP was never structured to be an arbiter of vaccine cost or a price-setting body: product cost commentary and scrutiny was never included within the Committee’s initial charge. Many immunizations carry large social and public health value that may transcend a simple cost-benefit analysis. Moreover, whether this process is suited to newer types of products used to target more severe but less prevalent health problems has emerged as a critical question. In general, the Committee’s role in cost evaluation remains unclear, and yet the issue will only intensify with the emergence of novel, costly technologies designed for highly targeted populations. But the importance of an ACIP recommendation could not be greater given its implications for free coverage as a mandatory preventive benefit. Whether ACIP should focus strictly on what can benefit patients rather than the broader health economy is a serious question, especially in a health equity context.

Perhaps the deepest underlying driver of modern ACIP policy is the remarkable advances in immunization technology over the past 60 years. Technology has enabled traditional vaccines to achieve stronger, longer-lasting immune responses; new products such as the HPV vaccine can prevent non-communicable outcomes such as cancer, and there are now products that historically were considered drugs but are capable of achieving long-acting prevention. One prime example of such newly emerging products is the RSV immunization for infants and children, known as Beyfortus, which was added to the ACIP schedule in 2023; as a monoclonal antibody, the RSV immunization technically works differently from traditional vaccines by directly delivering antibodies rather than prompting the immune system to develop its own response. The addition of Beyfortus to the schedule became possible only after the Biden Administration quietly expanded the ACIP’s charter to broaden its review authority over immunization products that fall into a separate classification from vaccines. This explicit expansion of the ACIP charter opens new vistas to many such products. But it simultaneously underscores the challenges facing the ACIP in terms of the scope of its authority and the sufficiency of its committee and staffing structure as its review role continues to expand.

An additional, external policy driver is the changing public perception of vaccines and the need for new approaches to vaccine communication. Americans who were children in the age of polio recall mass population campaigns and widespread acceptance. With the notable exception of the 2020 launch and roll-out of the COVID-19 vaccine, the evolving landscape and vaccine pipeline now looks to more targeted efforts in the face of vaccination’s shift from a response to widespread outbreaks and pandemics to a response to low prevalence, but highly serious, endemic diseases.  Moving from broad public health efforts to precision vaccinology triggers an entirely new context for public communication, and with it, new approaches to recommendation development for products that may have targeted properties rather than broad prevention across a mass population. Appropriately framing and communicating recommendations takes on added importance given the complexity of these new products as well as the social and political tensions that now surround vaccines.

In conclusion, six decades after its creation, the ACIP carries vastly expanded responsibilities, and its recommendations carry substantially greater impact. The importance and scope of its powers are best illustrated, perhaps, by HHS and CDC’s quiet but undeniably powerful decision to expand the ACIP charter to broaden its authority both to health care and, as a result, health care financing itself. The task that lies ahead now is to address the ACIP’s structural and procedural limitations to better ensure its ability to carefully deliberate the benefits and cautionary considerations that vaccine and immunization technology raise. Although the most important step in the ACIP’s existence was the decision to integrate its recommendations directly into insurance policy, the current challenge is to ensure that the Committee is up to the task, not only in terms of its structure and composition, but in its analytic methods and, ultimately, its values and technical and communication skills needed to set the parameters of immunizations and their financing in a transformed health care system.

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