ELK GROVE VILLAGE, ILL--The American Academy of Pediatrics (AAP) has issued its year 2000 childhood immunization schedule for the United States. The statement represents unified recommendations from the AAP, the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention, and the American Academy of Family Physicians. Specific changes in the schedule over the course of the past year include:

• Suspending use of the rotavirus vaccine.
• Using inactivated polio vaccine (IPV) instead of the oral polio vaccine (OPV) for all four doses of the vaccine.
• Recommending hepatitis A virus vaccine in certain states where the disease is most prevalent.

"The AAP anticipates that during the year 2000, additional vaccines will be approved, including ones for pneumococcal infections, which can cause bacterial meningitis and pneumonia, and bloodstream infections," said Michael Gerber, MD, FAAP, who is a member of the AAP Committee on Infectious Diseases.

Immunizations have reduced vaccine-preventable infectious diseases in the United States by more than 95% to 99% and have had a dramatic impact on reducing childhood morbidity and mortality, according to the AAP.

The updated childhood immunization schedule indicates the recommended ages for routine administration of childhood vaccines licensed as of November 1, 1999 (see Table 1). A licensed combination vaccine may be used whenever any components of the combination are indicated and its other components are not contraindicated. Revisions to the immunization schedule are as follows:

Hepatitis B: Infants born to HBsAg-negative mothers should receive the first dose of hepatitis B vaccine by age 2 months. The second dose should be given at least one month after the first dose; the third dose should be administered at least four months after the first dose and at least two months after the second dose, but not before age 6 months. Infants born to HBsAg-positive mothers should receive hepatitis B vaccine and 0.5 mL hepatitis B immune globulin (HBIG) at separate sites within 12 hours of birth. The second dose is recommended at 1 month of age and the third dose at age 6 months.

Infants born to mothers whose HBsAg status is unknown should receive hepatitis B vaccine within 12 hours of birth. Maternal blood should be drawn at the time of delivery to determine the mother's HBsAg status; if the HBsAg test is positive, the infant should receive 0.5 mL HBIG as soon as possible (no later than 1 week of age).

All children and adolescents (through age 18 years) who have not been immunized against hepatitis B may begin the series during any visit. Special efforts should be made to immunize children who were born, or whose parents were born, in areas of the world with moderate or high endemicity of hepatitis B virus infection.

DTaP: The fourth dose of DTaP (diphtheria and tetanus toxoids and acellular pertussis vaccine) may be administered as early as 12 months of age, provided that six months have elapsed since the third dose and that the child is unlikely to return for vaccination at age 15 to 18 months. Tetanus and diphtheria toxoids vaccine (Td) is recommended for children ages 11 to 12 years provided that at least five years have elapsed since the last dose of DTP, DTaP, or DT. Subsequent Td booster shots are recommended every 10 years.

Haemophilus influenzae: Three H influenzae type b (Hib) conjugate vaccines are licensed for infant use. If PRP-OMP (PedvaxHIB or ComVax) is administered at 2 and 4 months of age, a dose at 6 months is not required. Because clinical studies in infants have demonstrated that using some combination products may induce a decreased immune response to the Hib vaccine component, DTaP/Hib combination products should not be used for primary immunization in infants at 2, 4, or 6 months of age unless FDA-approved for those ages.

Poliomyelitis: To eliminate the risk of vaccine-associated paralytic polio (VAPP), an all-IPV schedule is now recommended for routine childhood polio vaccination in the United States. All children should receive four doses of IPV at age 2 months, 4 months, 6 to 18 months, and 4 to 6 years. OPV (if available) may be used only for the following special circumstances:

• For mass vaccination campaigns to control outbreaks of paralytic polio.
• For unvaccinated children who will be traveling in less than four weeks to areas where polio is endemic or epidemic.
• For children of parents who do not accept the recommended number of vaccine injections. These children may receive OPV only for the third or fourth dose or both; in this situation, health care professionals should administer OPV only after discussing the risk of VAPP with parents or caregivers.

During the transition to an all-IPV schedule, recommendations for the use of remaining OPV supplies in physicians' offices and clinics have been issued by the AAP.

Measles, mumps, and rubella: The second dose of measles, mumps, and rubella vaccine is recommended routinely at age 4 to 6 years but may be administered during any visit, provided at least four weeks have elapsed since receipt of the first dose and both doses are administered beginning at or after age 12 months. Children who have not received the second dose should complete the schedule by age 11 to 12 years.

Varicella: This vaccine is recommended at any visit for susceptible children age one year or older, including those who lack a reliable history of chickenpox (as judged by a health care professional) and who have not been immunized. Susceptible persons age 13 years or older should receive two doses, given at least four weeks apart.

Hepatitis A: This is indicated for use only in selected states and/or regions.