The Advisory Committee on Immunization Practices (ACIP) is a committee of experts who make recommendations to the Department of Health and Human Services (HHS) regarding the use of vaccines and related agents for the control of vaccine-preventable disease in the U.S. civilian population. As a critical function, ACIP recommendations have informed the Centers for Disease Control and Prevention's (CDC's) annual immunization schedules of recommended vaccines for both children and adolescents (18 years of age and younger) and adults (19 years of age and older). ACIP has also made recommendations for nonroutine vaccines, including for travel or for emergencies such as disease outbreaks.
On June 9, 2025, HHS Secretary Robert F. Kennedy Jr. removed the 17 then-sitting ACIP committee members and has since appointed several new members. To date, ACIP's official charter and its policy manual have remained as they were prior to the current Administration. This CRS InFocus summarizes ACIP's policies and practices based on these official documents.
The Surgeon General established ACIP in March 1964 under Section 222 of the Public Health Service Act (PHSA; 42 U.S.C. §217a), a general authority that allows appointment of advisory committees. ACIP was created to provide ongoing expert advice to the Surgeon General on federal immunization policy as several new vaccines came to market and federal immunization programs expanded (the Surgeon General oversaw federal immunization programs at the time). In 1972, ACIP was designated a federal advisory committee under the Federal Advisory Committee Act (FACA, P.L. 92-463; provisions of FACA have moved to 5 U.S.C. Chapter 10).
Since 1972, ACIP has provided recommendations to CDC, a leading federal agency for immunization programs. Per FACA requirements, its official charter outlines its objectives, scope of activities, and duties. The committee remains authorized under general authority. However, under several federal laws, ACIP and its recommendations play a role in defining the relevant statutory requirements (as explained in the "Statutory Roles" section).
Per its charter, ACIP can consist of up to 19 voting members who have clinical, scientific, and public health expertise in immunization. One lay member is a consumer representative with knowledge about social and community aspects of immunization programs. In addition, several federal health officials and liaison representatives from national health organizations (e.g., American Academy of Pediatrics, AAP) serve as nonvoting representatives.
Voting members are appointed by the HHS Secretary and serve overlapping terms of up to four years. Anyone can apply to become a member. Per its policy, the department seeks to balance committee membership in terms of points of view, professional training, and backgrounds. Voting members serve as Special Government Employees and must meet related federal ethics requirements.
ACIP recommendations regarding vaccines and their use are related to, but distinct from, the U.S. Food and Drug Administration's (FDA's) licensure or authorization of vaccines. Per its charter, ACIP recommendations are focused on the control of vaccine-preventable diseases, whereas FDA generally focuses its review on the safety and efficacy of vaccines and the processes used to manufacture them. ACIP typically makes its recommendations after FDA has approved or authorized a new vaccine (or an existing vaccine for a new indication). As required by the 21st Century Cures Act of 2016 (Cures Act; P.L. 114-255, as amended, §3091), ACIP must consider any newly licensed vaccine (or new indication) at the committee's next regularly scheduled meeting. In addition, ACIP may also make recommendations regarding other medical products (e.g., antimicrobial therapy) shown to be effective against a disease for which a vaccine is available.
Based on available evidence, ACIP weighs whether the benefits of recommending a certain vaccine for a certain population—including the impact of such a recommendation on disease transmission or reduction in disease, hospitalizations, and deaths—outweigh any possible harms at an individual or population level. Harms could include, for example, considerations around vaccine safety (individual level) or disease distribution within the population (population level). ACIP also considers the potential public health importance, quality of the evidence used, implementation considerations, equity, and values and preferences of the people affected. In a few cases, ACIP's recommendations have differed from FDA-approved indications for use, resulting in recommendations for "off-label" use of vaccines.
ACIP holds full-committee public meetings at least three times per year to review evidence and vote on new recommendations. Outside these meetings, ACIP members serve on work groups to review evidence regarding specific vaccines on an ongoing basis. According to the latest guidance from 2018, each work group consists of two ACIP voting members and a CDC subject matter expert, and may include nonvoting liaison representatives, such as from national health organizations. According to media reporting, as of July 31, nonvoting liaison representatives may no longer participate in work group meetings.
ACIP work groups typically present evidence reviews and draft recommendations to the full committee for public consideration. Final recommendations must receive a vote from a majority of the committee.
ACIP structures its recommendations to inform clinical practice. ACIP recommendations include (1) the age and other population groups (e.g., by sex, occupation) recommended to receive that vaccine; (2) the recommended age or frequency to receive each dose and the interval between doses (for multidose vaccines); and (3) any precautions and contraindications. Some ACIP recommendations are made for all people in a certain age group, whereas others are risk-based or targeted to specific patients in specific circumstances (e.g., travel vaccines). ACIP recommendations are also made in two categories:
ACIP may revise its previous recommendations based on new evidence or new circumstances, such as disease outbreaks or vaccine shortages. Some ACIP recommendations are issued as "interim" recommendations, meaning that they may be subject to change.
ACIP's recommendations are not automatically adopted as official federal recommendations. The CDC Director reviews and decides whether to formally adopt ACIP's recommendations. Official recommendations are published in the CDC Morbidity and Mortality Weekly Report. In emergency situations, CDC may issue a vaccine recommendation without ACIP consultation.
In recent years, ACIP has voted on the entire child and adult immunization schedules once per year. These schedules were updated to reflect all recommendations ACIP made each year regarding vaccines recommended for routine use. From 1995 until 2024, ACIP/CDC harmonized its immunization schedules with nonfederal health groups such as AAP and the American Academy of Family Physicians. In 2025, physician groups such as AAP have published separate immunization schedules from CDC.
As required by the Cures Act (§3091), ACIP is to make recommendations "in a timely manner, as appropriate" for vaccines that could be used in a public health emergency. During the COVID-19 pandemic, ACIP made two types of recommendations. First, ACIP made recommendations regarding the use of vaccines by age group following FDA authorizations or approvals. Second, in the early stages of the vaccine distribution program, ACIP made recommendations regarding the allocation of vaccines, specifically priority groups to receive the limited supply of vaccines. For example, in December 2020, ACIP recommended that health care personnel and residents of long-term care facilities receive COVID-19 vaccines first.
ACIP remains authorized under general authority of the HHS Secretary. Some laws, such as the Cures Act, have addressed ACIP and its recommendation process. In addition, ACIP's recommendations play a role in defining some statutory requirements, for example:
According to the Association of State and Territorial Health Officials' review of over 600 state and territorial laws and regulations that reference ACIP, such laws may direct the use or consideration of ACIP recommendations in several circumstances, including in defining the scope of (1) immunization requirements for school enrollment and attendance, (2) vaccine coverage by certain health plans, and (3) immunizations certain health care professionals (such as pharmacists) are authorized to administer.