The collaboration of the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP) continues with the 2001 Recommended Childhood Immunization Schedule (see page 152). Several important changes occurred this year and AAFP had active input into the schedule.

Whereas the schedule previously showed a preference for administering hepatitis B vaccine at birth, there is no longer such a preference because combination vaccines that include hepatitis B are now available. One such combination vaccine is currently licensed and another may be licensed in the near future. Nonetheless, children born to mothers who are positive for hepatitis B surface antigen should receive hepatitis B immune globulin and the first dose of hepatitis B vaccine within the first 12 hours of birth. Hepatitis B vaccine for children is now free of thimerosal as are Haemophilus influenzae type b (Hib) conjugate vaccines.

For 2001, the all-inactivated poliovirus vaccine (IPV) is recommended to eliminate the risk of vaccine-associated paralytic poliomyelitis (VAPP) that can occur with administration of oral poliovirus vaccine (OPV). Because of the risk of VAPP, the majority of parents prefer a vaccine schedule that starts with IPV even though extra injections are required.

The biggest change in the routine schedule is the addition of pneumococcal conjugate vaccine (PCV). Streptococcus pneumoniae causes approximately 3,000 cases of meningitis, 61,000 cases of bacteremia, 100,000 to 135,000 cases of pneumonia requiring hospitalization and 7 million cases of otitis media annually in the United States.¹ Risk factors for invasive pneumococcal disease include age, race, recent use of antibiotics, day care attendance, passive smoking and chronic medical conditions such as sickle cell disease and human immunodeficiency virus (HIV) infection. Heightening the importance of immunization is the increasing proportion of S. pneumoniae that is resistant to antibiotics.

A heptavalent PCV was licensed in the year 2000 in the United States. The vaccine is immunogenic.^2,3 The carrier protein is CRM₁₉₇, which has been used in one Hib vaccine. PCV does not contain thimerosal. The vaccine was designed to cover the seven serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) most common in children; in fact, these serotypes account for about 80 percent of invasive infections in children younger than six years but only 50 percent of infections in those six years and older.

A randomized, double-blind, controlled trial⁴ was conducted at Northern Kaiser Permanente (Calif.). In the primary analysis, the efficacy of PCV was 100 percent. Eight months later in the follow-up analysis, the vaccine efficacy against invasive disease was 94 percent for serotypes included in the vaccine in the intent-to-treat analysis and 97 percent for serotypes in the vaccine among patients who were fully vaccinated. No serious adverse reactions were associated with PCV. When PCV was given with diphtheria and tetanus toxoids and acellular pertussis but at another injection site, fever of 38°C (100.4°F) occurred in 15 to 24 percent of those vaccinated with PCV compared with 9 to 17 percent of those receiving the control vaccine (experimental meningococcal conjugate vaccine).⁴ Among persons receiving PCV, 10 to 14 percent developed redness at the injection site and 15 to 23 percent developed tenderness at the injection site.⁴ The break even price is $46 per dose from the societal perspective and $18 per dose from the health care payer's perspective.⁵ The manufacturer's list price is $58 per dose, making it the most expensive routine infant immunization series to date.

The AAFP, ACIP and AAP recommend PCV for routine infant immunization and catch-up vaccination of children younger than 24 months and catch-up vaccination of children 24 to 59 months of age at high risk for invasive disease, including sickle cell disease, HIV infection, chronic illness (e.g., bronchopulmonary dysplasia) and immunocompromising conditions. For infants, the routine vaccine schedule is two, four, six and 12 to 15 months. A special schedule is needed for catch-up vaccinations because the number of doses varies by age and by presence of high-risk medical conditions; see the manufacturer's package insert or ACIP recommendations. The information on the minimal age for initial childhood vaccinations and minimal interval between vaccine doses, by type of vaccine, is given in the accompanying table on page 154.⁶

Recent data indicate that allergy to gelatin is responsible for rare anaphylactic reactions to measles-mumps-rubella vaccine. Therefore, persons with anaphylaxis to gelatin should not receive vaccines containing gelatin. Clinicians should have epinephrine available for treating reactions following vaccination.

Federal law requires physicians to provide the federal Vaccine Information Statements to the patient or his or her parent or guardian for almost all childhood vaccines. The Vaccine Information Statements change periodically. An up-to-date set can be downloaded each January from the Web site of the Centers for Disease Control and Prevention (http://www.cdc.gov) or obtained from local health departments.

Progress in the development of new vaccines continues at an amazing rate. Physicians should be diligent to keep current; the following Web sites may be helpful:https://www.aafp.org;http://www.cdc.org/nip; andhttp://www.immunize.org.