The Development of the Immunization Schedule
The United States Department of Health and Human Services and the Centers for Disease Control and Prevention offer Child and Adolescent Immunization Schedules for children aged 0-6 years and 7-18 years, as well as a “catch-up schedule” for kids four months to 18 years old who may have missed recommended vaccinations. All of these schedules are approved by the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP).
Some vaccinations have been recommended in the United States since the 1940s, although the official annual schedule endorsed by ACIP, AAP, and AAFP did not appear until 1995. A combined vaccine for diphtheria, tetanus, and pertussis (whooping cough) was recommended in the 1940s; a combined vaccine for those three diseases is still recommended today. The smallpox vaccine, on the other hand, was on the schedule in the 1940s but is no longer recommended, as smallpox was declared eradicated in 1980 and eliminated from the United States much earlier.
The newly developed vaccine for polio was recommended in the 1950s. The specific vaccine used has changed since then, but polio vaccine remains on the current schedule. The combined measles, mumps, and rubella vaccine was added to the list of recommendations in the 1970s, after vaccines for all three diseases were developed in the 1960s.
The resulting recommended vaccination list included vaccines for seven diseases in the 1970s:
- Pertussis (whooping cough)
Protection for the remaining seven diseases on the schedule, however, required only three vaccinations:
- Polio vaccination
- Combined vaccination for Tetanus, Diphtheria, and Pertussis (DTP vaccine)
- Combined vaccination for Measles, Mumps, and Rubella (MMR vaccine).
The list of recommended vaccines continued to be updated as vaccines were developed for more diseases. The Hib (Haemophilus influenzae type b) vaccine was added to the list in the late 1980s, while a vaccine for hepatitis B was added in the mid-1990s. In 1995, the ACIP, AAP, and AAFP began issuing annual updates to the schedule. The annual updates contained detailed information about the recommended vaccines, including specific age- and dosage-related information, as well as information about new vaccines as they were added to the schedule. Since then, a number of vaccines have been added, including those for chickenpox (varicella) and hepatitis A, while others have been removed or replaced. (The first rotavirus vaccine added to the schedule was removed because of an association between the vaccine and intussusception, a type of bowel obstruction. It was later replaced with a different rotavirus vaccine that has no association with the condition.)
As of 2010, the schedule of children ages 0-6 years includes recommendations for the following vaccinations:
- Hepatitis B
- Diphtheria, Tetanus, and Pertussis (combined DTaP vaccine)
- Hib (Haemophilus influenzae type b)
- Polio (inactivated vaccine)
- Measles, Mumps, and Rubella (combined MMR vaccine)
- Varicella (chickenpox)
- Hepatitis A
In addition, the 7-18 years schedule recommends vaccination against human papillomavirus (HPV), and includes details regarding the conditions HPV vaccine prevents and the age and dosing suggestions for various risk groups.
These schedules are reviewed annually; new vaccines are considered for addition to the schedule after licensure, though not all licensed vaccines are added to the schedule. (The yellow fever vaccine, for example, is unlikely to be added to the schedule, as only individuals traveling to yellow fever endemic areas need to be vaccinated against it.)
Timeline Entry: 1972 Routine U.S. Smallpox Vaccination Ceases
Recommendations for routine U.S. smallpox vaccination, previously recommended at age 1, ceased.
As smallpox disappeared, the risks from complication of vaccination became less acceptable to the medical establishment and to the public. The graphic shows vaccination complications in 1968. The high number of revaccinations stems from the fact that vaccination-induced immunity waned over time. Revaccination was often performed 10-15 years after primary vaccination to ensure continuing immunity.See This Item In The Timeline
Timeline Entry: 1997 IPV Returns to U.S. Schedule
An improved version of Jonas Salk’s inactivated poliovirus vaccine began to be given to U.S. children before giving the OPV that had been a standard part of the immunization schedule since 1968. An average of 8-10 cases of vaccine-derived polio per year were caused by the OPV (about 1 case per 2.4 million doses distributed). Among OPV recipients, the risk was higher with first doses (1 per 750,000 doses), compared with subsequent doses (1 per 5.1 million doses). In the absence of wild-type disease, the public and authorities began to deem the risk from the vaccine unacceptable.
By 2000, transition to an all-IPV schedule would be complete.See This Item In The Timeline