plexity that affect the national immunization system, and then reviews examples of success and problem areas.
Key areas of change affecting the national immunization effort include (1) the immunization schedule, (2) the nature of infectious disease, and (3) population demographics.
Ever since the American Academy of Pediatrics (AAP) offered the first immunization guidelines in the 1930s, scientific developments have led to regular changes in the recommended immunization schedule. The rate of change has increased dramatically in the last decade and is likely to continue accelerating in the next 20 years (see Figure 2–1). Between 1938 and 1985, five vaccines (three childhood and two adult) comprising nine different antigens were available. In the next 15 years, the number of recommended vaccines more than doubled.
To complete the current harmonized childhood immunization schedule,1 children must receive 15 to 19 doses of vaccine before 18 months of age and a total of 19 to 22 doses to be fully immunized by the age of 6 (see Figure 1–1 and Table 1–3 in Chapter 1). During some office or clinic visits, the administration of 3 or 4 separate injections is indicated. Adolescents are to receive a tetanus shot between ages 11 and 15, as well as measles, mumps, and rubella (MMR), varicella, and hepatitis B vaccinations if these were not administered at a younger age.
Immunization recommendations for adults have recently changed. The Advisory Committee on Immunization Practices (ACIP) currently recommends that all adults over age 50 receive an annual influenza vaccine (CDC, 2000a). One-time pneumococcal immunizations are recommended for all adults age 65 and over (although ACIP is considering a proposal to lower this recommendation to age 50). Both influenza and pneumococcal immunizations are recommended for anyone below age 65 with certain high-risk conditions, such as heart and lung disease, diabetes, and a compromised immune system. In certain situations, depending on age and health status, adults are also advised to receive hepatitis A, hepatitis B, tetanus, diphtheria, measles, mumps, rubella, and varicella vaccinations (see Table 1–3). Meningococcal vaccine is now recommended for college students, especially those living in dormitories.
Repeated changes to the immunization schedule in the last 5 years foreshadow the exponential changes anticipated in the future. These recent changes include the following: