The Advisory Committee on Immunization Practices (ACIP) and the Childhood Immunization Schedule

  • The Centers for Disease Control and Prevention (CDC) sets the U.S. childhood immunization schedule based on recommendations from the Advisory Committee on Immunization Practices (ACIP).
  • Before recommending a vaccine the ACIP considers many factors, including the safety and effectiveness of the vaccine.
  • Candidates for ACIP membership are screened carefully prior to being selected to join the committee.
  • The ACIP develops vaccine recommendations for children and adults. The recommendations include the age(s) when the vaccine should be given, the number of doses needed, the amount of time between doses, and precautions and contraindications.

Questions and Answers

What is the ACIP?

The Advisory Committee on Immunization Practices (ACIP) is a group of medical and public health experts that develops recommendations on how to use vaccines to control diseases in the United States.

The ACIP consists of 15 experts who are voting members and are responsible for making vaccine recommendations. The Secretary of the U.S. Department of Health and Human Services (DHHS) selects these members after an application, interview, and nomination process. Fourteen of these members have expertise in vaccinology, immunology, pediatrics, internal medicine, nursing, family medicine, virology, public health, infectious diseases, and/or preventive medicine. One member is a consumer representative who provides perspectives on the social and community aspects of vaccination.

The ACIP works with 30 professional organizations that are highly regarded in the health field. Examples of these professional organizations with which ACIP develops the annual harmonized childhood schedule are the American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP). These members comment on ACIP’s recommendations and offer the perspectives of groups that will implement the recommendations.

Certain people are not considered for ACIP membership. For example, people who are directly employed or have an immediate family member directly employed by a vaccine manufacturer, hold a patent on a vaccine or related product, or serve on a Board of Directors of a vaccine manufacturer are excluded from ACIP membership. However, because ACIP members are experts in the vaccine field, they may be involved in vaccine studies.

Therefore, people who lead vaccine studies at their respective institutions may become ACIP members, but they must abstain from voting on recommendations related to the vaccine they are studying. In addition, they cannot vote on any other vaccines manufactured by the company funding the research or on any vaccines that are similar to the one(s) they are studying.

Adults Need Vaccines Too

Adults also need protection against several vaccine-preventable diseases. Therefore, in addition to the childhood immunization schedule, the ACIP makes recommendations for the adult immunization schedule. The ACIP considers many of the same factors for adult immunization recommendations that they consider when making recommendations about the childhood schedule. The professional organizations that work with the ACIP to develop the annual adult schedule include the American College of Obstetricians and Gynecologists (ACOG), the American College of Physicians (ACP), the American Academy of Family Physicians (AAFP), and the American College of Nurse Midwives.

How does ACIP make decisions about vaccine recommendations?

The ACIP holds three meetings each year at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia to make vaccine recommendations. Meetings are open to the public and available online via webcast. During these committee meetings, members review findings and discuss vaccine research and scientific data related to vaccine effectiveness and safety, clinical trial results, and manufacturer’s labeling or package insert information. Outbreaks of vaccine-preventable disease or changes in vaccine supply, such as vaccine shortages, also are reviewed during these meetings. The recommendations include the age(s) when the vaccine should be given, the number of doses needed, the amount of time between doses, and precautions and contraindications.

In addition to these meetings, ACIP members participate in work groups. These work groups are active all year to stay up-to-date on specific vaccines and vaccine safety information. For example, before a vaccine is even licensed by the U.S. Food and Drug Administration (FDA), an ACIP work group will thoroughly review all available scientific information about the vaccine so that they will be prepared to present information to the ACIP about the vaccine once it is licensed. At this point, the vaccine already has undergone several phases of testing for safety and efficacy with potentially hundreds or thousands of volunteers. The licensure process can take several years. The work group carefully reviews data available on the vaccine in order to make recommendations to the ACIP, but work groups do not vote on the final recommendation. The work group presents its findings to the entire ACIP at several meetings before ACIP members vote on whether to recommend the vaccine and who should receive the vaccine. Once the CDC Director and DHHS have approved the ACIP recommendations, they are published in CDC’s Morbidity and Mortality Weekly Report (MMWR). Upon publication, the recommendations represent the official CDC recommendations for immunizations in the U.S.

Each year, the ACIP’s recommendations result in a childhood immunization schedule for birth through age 18 years old, approved by the CDC, AAP, and AAFP, and designed to best protect children in the United States.

What does the ACIP consider in the vaccine recommendation process?

The information that ACIP reviews for each vaccine always includes the following:

  • The safety and effectiveness of the vaccine when given at specific ages. Only vaccines licensed by the FDA are recommended, and vaccine manufacturers must conduct rigorous studies to show that a vaccine is safe and effective at specific ages.
  • The severity of the disease. Vaccines recommended for children prevent diseases that can be serious for them, potentially causing long-term health problems or death.
  • The number of children who get the disease if there is no vaccine. Vaccines that do not provide benefit to many children may not be recommended for all children.
  • How well a vaccine works for children of different ages. The immune response from a vaccine can vary depending on the age when the vaccine is given.

What does the ACIP consider when deciding at what age children should receive different vaccines?

The risk of disease and death at different ages is a main factor in deciding the best age to give each vaccine. The ACIP carefully examines data about each vaccine-preventable disease to determine at what ages the rates of the disease peak. Protection against vaccine-preventable disease at the earliest time possible is critical, especially for young children or other high-risk groups, for whom a disease can be especially serious. For example, pertussis vaccine is recommended in the United States beginning at 2 months of age to protect infants. That timing saves lives that would otherwise be lost to the disease if vaccines were not given at a very young age.

The immunization schedule also is based on balancing the risk of being exposed to the disease against the added protection of vaccinating at the age that a vaccine works best. Before a vaccine is licensed by the FDA, extensive testing is done to determine the best ages to safely and effectively give the vaccine.

Where can I find ACIP’s vaccine recommendations?

All of the ACIP’s recommendations are posted on the CDC webpage at Once they are reviewed and approved by the CDC Director and DHHS, recommendations are published in the CDC’s Morbidity and Mortality Weekly Report (MMWR). The MMWR publication represents the final and official CDC recommendations for immunizations of the U.S. population.

How can I learn more about the ACIP?

To learn more about the ACIP and see the schedule of ACIP meetings, review minutes and recommendations from previous meetings, and register for future meetings, visit the ACIP website.