The 2005 Recommended Childhood and Adolescent Immunization Schedule (see accompanying charts), which is approved by the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP), is similar to the July to December 2004 schedule. One item change should be noted: influenza vaccine is now recommended for routine use in children six through 23 months of age. This is indicated by the yellow bar for influenza located above the red dotted line for children six to 23 months of age; it also is recommended for children two years of age and older who have risk conditions such as asthma.

Hospitalization rates from influenza are highest among preschoolers, especially infants zero to one year of age. Among children aged zero to two years, the influenza-related hospitalization rates range (depending on the exact age) from about 800 to 1,900 per 100,000 for children who have high-risk conditions compared with 186 to 1,038 per 100,000 for healthy children.^1–3 One study⁴ found rates of 144 to 187 per 100,000 children aged zero to 23 months.^2,4 Furthermore, one team showed that healthy children aged six months to three years had rates of influenza-associated hospitalization as high or higher than rates among children aged three to 14 years who had high-risk conditions.^1,3 One study³ found that for every 100 children, an annual average of six to 15 outpatient visits and three to nine courses of antibiotics were attributable to influenza. Recently, neurologic complications of influenza in children have been more widely recognized, including encephalopathy and death.

Influenza is common among children. The illness attack rate is highest in children, at 14 to 40 percent yearly, with attack rates typically over 30 percent in preschool-aged children.^5–7

Trivalent inactivated influenza vaccine (TIV) has moderate efficacy in young children and good efficacy in older children. A study⁸ of children aged one through 15 years found TIV to be 77 to 91 percent efficacious against influenza type A respiratory illness with efficacy defined by seroconversion of 44 to 49 percent among children one to five years of age, 74 to 76 percent among children six to 10 years of age, and 70 to 81 percent among children 11 to 15 years of age. Another study⁹ found an efficacy rate of 56 percent against influenza illness among children aged three to nine years. In the first year of a third study,¹⁰ efficacy was 66 percent against culture-confirmed influenza among children six to 24 months of age.

Because TIV is not live, it cannot cause influenza. Influenza vaccine can cause local reactions such as soreness at the injection site. In young children who have not been exposed to influenza vaccine, fever, malaise, and myalgia can occur. In one trial, fever occurred in 11.5 percent of children one to five years of age and in 5 percent of children aged six to 15 years.⁸ One study¹¹ from the Vaccine Safety Datalink found that no serious reactions were associated with influenza vaccination among 251,600 children younger than 18 years of age who received over 438,000 doses of inactivated influenza vaccine. The Centers for Disease Control and Prevention’s (CDC’s) Vaccine Information Statement on Influenza has been updated and is available on the CDC Web site athttp://www.cdc.gov/nip/publications/VIS/default.htm.

Useful Web sites for current immunization information include the following: the CDC National Immunization Program Web site (http://www.cdc.gov/nip); the AAFP Web site (https://www.aafp.org), which contains AAFP clinical policies on immunization; the Group on Immunization Education of the Society of Teachers of Family Medicine’s Web site (http://www.immunizationed.org), which is a site developed by family physician educators and has free Palm OS and Windows applications of the childhood schedule; the Immunization Action Coalition Web site (http://www.immunize.org); and the National Network for Immunization Information Web site (http://www.immunizationinfo.org).