When you roll up your sleeve to get your annual flu shot or when parents take their children for routine vaccinations, a careful scientific process has already determined that these vaccines are both safe and necessary. Behind these recommendations stand two crucial but often overlooked committees that have been quietly protecting public health for decades. The Advisory Committee on Immunization Practices (ACIP) at the Centers for Disease Control and Prevention (CDC) and the Vaccines and Related Biological Products Advisory Committee (VRBPAC) at the Food and Drug Administration (FDA) represent the backbone of America’s vaccine policy system.
These committees emerged from hard-learned lessons about the need for systematic, science-based decision-making in vaccine policy. Understanding their history and function reveals how the United States built one of the world’s most trusted and effective immunization programs, even as these institutions face new challenges in an era of increasing vaccine hesitancy and political polarization.
When Ad Hoc Advice Wasn’t Enough
To understand why these committees were created, we need to travel back to the 1940s and 1950s, . During this period, the U.S. Public Health Service relied on temporary groups of experts who were brought together only when specific issues arose. These ad hoc committees (temporary groups formed for a particular purpose) would meet, offer their advice, and then disband.
The limitations of this approach became starkly apparent in 1955 with two pivotal events. First, Jonas Salk developed the first effective polio vaccine, a breakthrough that required immediate decisions about how to use this life-saving tool. Second, what became known as the “” occurred, where cases of paralytic polio resulted from incomplete inactivation of live poliovirus in vaccines produced by one manufacturer. This disaster underscored the crucial need for ongoing oversight and expert guidance, rather than crisis-driven responses.
By the early 1960s, new vaccines were being licensed regularly. The monovalent oral poliovirus vaccine was approved in 1961, followed by the trivalent oral poliovirus vaccine and measles vaccine in 1963. With increased federal investment in vaccines and immunization programs, it became clear that decision-making required “”.
The Birth of ACIP: Creating Systematic Vaccine Policy
In March 1964, . This marked a fundamental shift from reactive to proactive vaccine policy-making. ACIP was created to provide ongoing expert advice to the CDC and the Secretary of Health and Human Services on vaccine use in the civilian population.
When ACIP was first established, it comprised just eight members. Today, the committee can include up to 19 voting members who bring expertise in clinical medicine, scientific research, and public health aspects of immunization. The committee also includes one lay member who represents consumer perspectives and understands the social and community aspects of immunization programs. Additionally, several federal health officials and representatives from national health organizations serve as non-voting members.
ACIP meets three times per year in sessions that are open to the public. The committee's work follows a rigorous process that includes reviewing scientific literature on vaccine safety and effectiveness, assessing cost-effectiveness, examining disease-related morbidity and mortality, and considering the practical aspects of implementing vaccination programs. Since 2010, ACIP has used the (Grading of Recommendations Assessment, Development and Evaluation), which systematically evaluates the quality of evidence and strength of recommendations.
The committee's recommendations fall into two main categories. Standard recommendations apply to all people in a specific age or risk group, such as recommending that all children receive measles, mumps, and rubella vaccines. Shared clinical decision-making recommendations require individual discussions between healthcare providers and patients, taking into account personal risk factors and circumstances.
For example, imagine a 65-year-old person with diabetes considering whether to get a pneumonia vaccine. Under a standard recommendation, this would be automatically recommended for all people in this age and risk category. Under a shared clinical decision-making approach, the person would need to discuss with their doctor whether the benefits outweigh any potential risks based on their specific health situation. This second example is fictional but illustrates how the two types of recommendations work differently in practice.
ACIP's influence extends far beyond medical practice. . This means that ACIP recommendations directly determine which vaccines Americans can access without paying out of pocket. The committee's recommendations also determine which vaccines are included in the , which provides free vaccines to eligible children.
VRBPAC: The FDA's Vaccine Approval Gatekeepers
While ACIP determines how approved vaccines should be used, the handles the equally important question of which vaccines should be approved in the first place. VRBPAC operates under the and provides independent expert advice to the FDA on the safety, effectiveness, and appropriate use of vaccines and related biological products.
VRBPAC who are experts in fields such as immunology, molecular biology, virology, bacteriology, epidemiology, biostatistics, vaccine policy, vaccine safety science, infectious diseases, pediatrics, and biochemistry. Like ACIP, VRBPAC includes a representative from the pharmaceutical industry; however, this person does not have voting authority on committee decisions. The committee also includes a public representative to ensure that consumer perspectives are considered.
The committee’s meetings serve multiple purposes. When pharmaceutical companies submit applications for new vaccines, VRBPAC reviews the clinical trial data and other evidence to determine whether the benefits of the vaccine outweigh the risks. The committee also provides guidance on research programs and assists the FDA in navigating complex scientific questions related to vaccine development and safety monitoring.
According to a review of VRBPAC activities, the committee was brought together for an average of 4.1 sessions per year between 2000 and 2019, with about one-quarter of these sessions . In that same timeframe, the FDA granted 44 new vaccine licenses, with VRBPAC examining nearly half of these applications. This might seem like a relatively low percentage, but the FDA has discretion in deciding which vaccines require advisory committee review, often reserving VRBPAC consultation for more complex or controversial cases.
The transparency of VRBPAC meetings represents a crucial element of public trust in the vaccine approval process. As one expert noted, the independence of advisory committee members and the public nature of meetings, which allow outside observers to view clinical evidence and follow deliberations, .
How the Two Committees Work Together
While ACIP and VRBPAC have distinct roles, they work as complementary parts of a comprehensive system. VRBPAC’s work comes first in the timeline. When a pharmaceutical company develops a new vaccine, it must submit extensive data from clinical trials to the FDA. VRBPAC reviews this data and advises the FDA on whether the vaccine is safe and effective enough to be licensed for use in the United States.
Once the FDA approves a vaccine based on VRBPAC’s advice, the question shifts to how that vaccine should be used. This is where ACIP steps in. The committee examines not just the safety and effectiveness data that VRBPAC reviewed, but also broader questions about disease epidemiology (how diseases spread in populations), cost-effectiveness, and practical implementation issues.
Consider the recent example of COVID-19 vaccines. During the pandemic, VRBPAC met numerous times to review data from vaccine manufacturers and provide recommendations on . Once vaccines received FDA authorization, ACIP met to determine who should receive the vaccines first, how they should be distributed, and what the ongoing vaccination strategy should be. ACIP met dozens of times during the pandemic to guide the launch, expansion, and evolution of the vaccination program.
The relationship between these committees became particularly visible during the COVID-19 pandemic, when their meetings were livestreamed and closely watched by the public. This transparency enabled people to observe how vaccine policy decisions are made through careful scientific deliberation, rather than being influenced by political considerations.
The Authority Behind the Recommendations
Understanding the legal and practical authority of these committees helps explain why their decisions carry significant weight. ACIP operates under the general authority granted by , which allows the Secretary of Health and Human Services to convene advisory committees. While ACIP’s recommendations are not automatically binding, they carry significant practical weight due to their statutory role in determining insurance coverage and vaccine program eligibility.
When ACIP makes a recommendation, . If adopted, the recommendation is published in the CDC’s Morbidity and Mortality Weekly Report and becomes official federal policy. This establishes a direct connection between scientific expert advice and national health policy.
VRBPAC’s authority is more advisory in nature, but equally important. The committee’s recommendations help guide the FDA’s decisions about vaccine approvals, but the FDA is not required to follow VRBPAC’s advice. However, the FDA rarely disagrees with VRBPAC recommendations, and when it does, the agency provides detailed explanations for its decisions.
The practical impact of these committees extends throughout the healthcare system. Healthcare providers rely on ACIP’s immunization schedules as the standard of care for vaccination recommendations. Insurance companies use ACIP recommendations to determine coverage requirements. State and local health departments use these recommendations to design their immunization programs. Public health emergency responses often depend on rapid guidance from both committees and agencies.
Recent Challenges and Changes
The role and visibility of both committees have evolved significantly in recent years. The COVID-19 pandemic thrust both ACIP and VRBPAC into unprecedented public attention as they navigated the complex task of evaluating new vaccine technologies and developing recommendations for a rapidly evolving health emergency. .
However, recent political developments have created new challenges for both committees. Reports indicate that meetings have been , raising concerns about potential political interference in scientific decision-making processes. The confirmation of , as Secretary of Health and Human Services (HHS) has intensified scrutiny of these committees and their independence.
The tension between scientific independence and political oversight represents an ongoing challenge for both committees. As federal advisory committees, they must balance their role as independent scientific advisors with their position within politically appointed government structures. Recent events have highlighted the importance of maintaining scientific integrity in vaccine policy decision-making.
Before leaving office in January 2025, , potentially limiting the current administration’s ability to influence the committee’s composition until 2027. This action reflects the broader political significance these appointments have gained and the recognition that committee composition can influence vaccine policy directions.
A System Built on Scientific Rigor
The history of ACIP and VRBPAC reveals how the United States developed a systematic approach to vaccine policy that prioritizes scientific evidence over political considerations. Both committees emerged from recognition that effective vaccine policy requires ongoing expert oversight rather than ad hoc responses to crises.
The success of this system can be measured in multiple ways. The United States has one of the most comprehensive and effective childhood immunization programs in the world, largely due to the evidence-based recommendations developed by these committees. .
The transparency and rigor of both committees have helped maintain public trust in vaccines, even as misinformation and vaccine hesitancy have increased. The public nature of their meetings and the detailed documentation of their decision-making processes provide accountability that helps distinguish science-based recommendations from political or commercial interests.
Both committees continue to evolve their methods and approaches. ACIP's adoption of the GRADE framework represents an ongoing commitment to improving the quality and transparency of evidence evaluation. VRBPAC's increased engagement during the COVID-19 pandemic demonstrated the committee's ability to respond rapidly to public health emergencies while maintaining scientific rigor.
As these committees face new challenges in an era of increased political polarization and vaccine hesitancy, their historical foundation of scientific independence and public transparency becomes even more valuable. The careful deliberation and evidence-based approach that characterized their work for six decades provides a model for maintaining trust in public health institutions during uncertain times.
The story of ACIP and VRBPAC illustrates how effective public health policy emerges from sustained commitment to scientific excellence rather than quick political fixes. These committees represent the institutional memory and expertise that enable the United States to respond effectively to both routine immunization needs and emerging health threats. Their continued independence and scientific integrity will remain essential for protecting public health in the years ahead.
Sources and Additional Reading
- Smith, J. C., Hinman, A. R., & Pickering, L. K. (2014). History and evolution of the Advisory Committee on Immunization Practices—United States, 1964–2014. Morbidity and Mortality Weekly Report, 63(42), 955–958.
- Sekar, K. (2024, December 3). The Advisory Committee on Immunization Practices (ACIP) (CRS Report No. IF12317). Congressional Research Service.
- Kanter, G. P., Vallurupalli, N., Xu, Y., & Gupta, R. (2021, July 22). Vaccine approvals and the role of the FDA vaccine advisory committee, 2000–2019 [Preprint]. medRxiv.
- U.S. Food and Drug Administration. (2024, July 3). Charter of the Vaccines and Related Biological Products Advisory Committee.
- Health Affairs Forefront. (2024, September 17). Promoting resilience through the Advisory Committee on Immunization Practices.