Vaccine schedules and procedures, 2005

Journal of Family Practice, Jan, 2005 by Donald B. Middleton, Richard Kent Zimmerman, Karen B. Mitchell

This article presents the 2005 Recommended Childhood and Adolescent Immunization Schedule; the catch-up schedule; the 2004-2005 Recommended Adult Immunization Schedule, which will stay in effect for 2005; contraindications for immunization; and general guidelines on immunization procedures. Recent changes for children include institution of thimerosal-free hepatitis B vaccination either before hospital discharge or as soon after birth as possible and the recommendation to give inactivated influenza vaccine to all children who will be between the ages of 6 and 23 months during the influenza season. Minimal intervals between vaccines and vaccine precautions, contraindications, administration, and storage are reviewed. Sources of vaccine information are presented and discussed.

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Vaccination policy in the United States continues to be extraordinarily successful at reducing vaccine-preventable disease incidence in both children and adults. Previously widespread diseases such as Haemophilus influenzae type b (Hib) infections and measles, once major causes of morbidity and mortality, have been nearly eradicated, thanks to immunizations. (1) Only 17 cases of rubella were reported in 2003, reflecting great success, but an increasing number of cases of pertussis (11,647) in 2003 reflects the need for continued improvements. (2)

In 2004, the estimated cost to fully immunize a child was $472 for each of about 4 million children per year. Nonetheless, because of the costs associated with wild vaccine-preventable infections, the overall vaccine program has proven to be one of the most cost-effective public health measures in place. (3) This article will review the age-based recommendations that serve as the foundation for the national vaccine program in the United States and discuss contraindications, precautions, administration techniques, and storage procedures for routinely administered vaccines.

AGE-BASED IMMUNIZATION SCHEDULES

Children and adolescents

The Recommended Childhood and Adolescent Immunization Schedule (see color centerfold) is published each January in a number of sources, which are enumerated in the "Keeping current with vaccine recommendations" section of this article. The Recommended Adult Immunization Schedule is updated less frequently on an as-needed basis. Recent changes in the childhood vaccine schedule include:

(1) Providing all healthy newborn infants with their first hepatitis B vaccination prior to hospital discharge or as soon as possible thereafter.

(2) Administering inactivated influenza vaccine to all 6-to-23-month-olds and all caregivers of children age 0 to 23 months.

* Infants and hepatitis B vaccine

Hepatitis B vaccine is the only immunization recommended at birth. It is given to all newborn infants as soon as possible after birth, preferably prior to hospital discharge. The schedule for vaccinating infants against hepatitis B virus (HBV) depends on the mother's hepatitis B surface antigen (HBsAg) status and the infant's weight. (4) Currently, 5 different vaccine products are available to protect against HBV (TABLE 1). (5)

HBsAg-negative mothers, if the mother is HBsAg-negative, the first vaccine dose should be given at birth prior to hospital discharge or at any time before 2 months of age. The second dose is given at 1 to 4 months of age, at least 1 month after the first dose. The third dose is given at least 16 weeks after the first dose and 8 weeks after the second, preferably before 18 months of age but no sooner than 24 weeks of age (see Recommended Childhood and Adolescent Immunization Schedule in color centerfold).

HBsAg-positive mothers. Infants born to HBsAg-positive mothers should be given both hepatitis B vaccine and hepatitis B immune globulin (HBIG) within 12 hours of birth, regardless of gestational age or birth weight. (4) Ideally, infants weighing [greater than or equal to] 2000 g should receive the second dose of vaccine between the ages of 1 and 2 months and the third dose at 6 months of age. Low-birth-weight infants are discussed below. If a mother is chronically infected with HBV, her infant should be tested between the ages of 9 and 15 months for both HBsAg (to detect infection) and hepatitis B surface antibody, or anti-HBs (to prove successful vaccination).

Mothers with unknown HBsAg status. For infants born to mothers with unknown HBsAg status, hepatitis B vaccine should be given within 12 hours of birth regardless of gestational age or birth weight, (4) and maternal blood should be drawn at the time of delivery to determine HBsAg status. If the test result is positive, HBIG should be given as soon as possible but no later than 1 week of age. Because infants weighing <2000 g have unpredictable responses to HBV, they should receive HBIG within 12 hours of birth if their mothers' HBsAg status cannot be determined during that time.

Birth weight. Because seroconversion rates following hepatitis B vaccine are lower in premature infants weighing <2 kg and even lower for those below 1 kg, the optimum timing for administering hepatitis B vaccine to premature infants is in debate. (4,6) TABLE 2 lists current recommendations. (7) If the infant weighs <2 kg and the mother is HbsAg-positive, the initial dose of hepatitis B vaccine should not be counted toward completion of the vaccine series. (4) For these infants, hepatitis B vaccine should be repeated at 1 month, 2 to 3 months, and 6 to 7 months of age. (40 Consistent weight gain in preterm infants is a predictor of good immune response. Medically stable infants whose mothers are HBsAg-negative and who weigh <2 kg--especially those who are gaining weight or are well enough to be discharged from the hospital--may receive their first dose of hepatitis B vaccine at 30 days of age. (8) Despite the debate about timing, the decision to start the hepatitis B series in the nursery when an infant is 30 days of age, regardless of his/her weight, offers more options for completing the immunization schedule, reduces the number of injections due at 2 months of age, provides earlier protection to the vulnerable infant who may need blood products or surgical procedures, and lessens the risk of horizontal spread from occult HBV infection to other family members, hospital visitors, and caregivers. Additionally, studies have proven that the closer hepatitis B vaccine is given to birth, the greater the likelihood that the full complement of childhood vaccines will be completed on time. (8)