For Parents

How Childhood Vaccines Are Selected for Routine Use

Unlike drugs, which are used to treat sick people, vaccines are used in healthy people to prevent certain illnesses. Before a vaccine can be used in the United States, it must be shown to be safe and effective. To make these determinations, the U.S. Food and Drug Administration (FDA) conducts a rigorous review of data regarding the vaccine’s safety and efficacy. Because healthy children are typically the recipients of vaccines, safety requirements are especially stringent.

Many federal agencies and private organizations are involved in ensuring the safety of vaccines and for promoting the health of the population:

  • Food and Drug Administration
  • Centers for Disease Control and Prevention
  • National Vaccine Advisory Committee (U.S. Department of Health and Human Services)
  • National Institutes of Health
  • American Academy of Pediatrics
  • State legislatures

The Role of the FDA on Vaccine Licensure

The FDA regulates vaccines that are used in the United States, ensuring that they are shown to be safe and effective before they are approved for use. The vaccine first undergoes laboratory studies, then studies with animals, and then with humans. The results of the studies at every step in the process must show that the vaccine does what it is supposed to do, and that it does not harm people who receive it. The FDA also inspects the manufacturing plant and makes sure the vaccine is made in a safe and consistent manner.

Vaccine licensure is a lengthy process that may last up to 10 years. Vaccines must go through three phases of clinical trials in human beings before they are licensed for public use. To establish basic safety, Phase One trials are small, involving only 20-100 volunteers and lasting only a few months. To continue to gather information on efficacy and safety of each vaccine, Phase Two trials are larger (with several hundred volunteers), and last anywhere from a few months to a few years. Phase Three trials have several hundred to several thousand participants and typically last many years.

If the FDA approves the vaccine for use in humans, the manufacturer can market the vaccine. Each batch of vaccine made by the manufacturer must be tested for safety, potency, and purity before being put on the market. A sample from each lot must be sent to the FDA.

In addition, the FDA requires that doctors report reactions that occur after vaccination. More on this program may be found in the “Monitoring Vaccine Safety” section below.

How Vaccines Are Recommended

After a new vaccine is approved by the FDA, committees of experts decide whether it should be recommended for use in the general population. These committees evaluate the safety and effectiveness of vaccines. They also determine how the vaccine should be used, estimate how new recommendations would affect other health care issues, and consider cost-effectiveness issues.

In addition to making recommendations on new vaccines, the committees of experts also review and update recommendations on existing vaccines. The policies for vaccines change along with the changes in the threat of disease.

The committees of experts include:

  • Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention
  • Committee on Infectious Diseases (COID) of the American Academy of Pediatrics (Red Book)
  • American Academy of Family Physicians (AAFP)
  • American College of Physicians (Guide for Adult Immunization [Green Book])

ACIP is a scientific advisory committee with 10 to 15 members. Although ACIP is federally chartered, the experts are chosen from outside of government. For each vaccine, the ACIP reviews a broad range of materials:

  • Published and unpublished reports on the safety and efficacy of the vaccine
  • Records on the side effects and deaths associated with the disease
  • Labeling for the vaccine
  • Considerations of other groups

The ACIP considers how the use of the new vaccine might fit into existing child and adult immunization programs. The committee also considers how the vaccine is stored and administered, cost-effectiveness, how the vaccine might affect other health care delivery systems, and other factors.

Members of the COID are selected on the basis of their knowledge of infectious disease and their expertise in vaccines. In addition to the 12 core committee members, liaisons represent the FDA, CDC, and other organizations. COID works closely with these federal agencies and private organizations in an effort to avoid conflicting recommendations.

How Vaccine Use Becomes Law

Committees of experts make recommendations on the use of vaccines in the United States, but it is the responsibility of the individual states to determine which vaccines are required by law. It is up to states to pass and enforce compulsory immunization statutes.

School immunization laws are established to prevent epidemics of certain contagious diseases, such as measles. Currently, all 50 states have school immunization laws.

All 50 states allow children to be exempted from mandated immunizations for medical reasons. Nearly all (48) states allow religious exemptions and 20 allow philosophical exemptions. If an outbreak of a vaccine-preventable disease occurs, those children who are not vaccinated may be prohibited from going to school until the outbreak is resolved.

For further information, read Indications, Recommendations and Immunization Mandates.