WASHINGTON, DC—The American Academy of Pediatrics’ (AAP’s) Committee on Infectious Diseases has issued a policy statement on the prevention and treatment of influenza in children. The statement recommends immunization for children 6 months and older, but it acknowledges that a universal immunization program for children may not yet be logistically or economically feasible.[1]

Studies have shown that school-age children have the highest rates of influenza infection, with an annual attack rate between 15% and 42%. However, younger children—those younger than 24 months—are at greatest risk of hospitalization for influenza. Also at increased risk for flu-related complications are children with certain chronic conditions, such as asthma, cystic fibrosis, and sickle cell anemia. Influenza may also play a role in the development of acute otitis media in children during the flu season, and it adds significantly to the amount of antibiotics prescribed for children.

The only influenza vaccine currently licensed for use in children is the trivalent inactivated influenza vaccine (TIV), which is given as an injection. First-time vaccine recipients younger than 9 years must receive two doses, one month apart. The TIV has a low incidence of side effects but should not be given to children who are allergic to egg or chicken proteins.

The efficacy of the TIV varies annually, from 60% to 95%, depending on the antigenic match between circulating influenza viruses and those chosen for use in that year’s vaccine. However, studies in Japan and the United States have indicated that immunization of schoolchildren against influenza can decrease the incidence of influenza among all age-groups.

Questions about the cost savings generated by universal immunization of children must consider the costs of immunizing a single child—including supplies, personnel, and administrative expenses. Other factors include the influenza attack rate, as well as the rates of related outpatient physician visits and hospitalizations.

However, the most important cost factor may be the time parents or caregivers lose from work to have their children immunized. Studies have concluded that a universal immunization program for children might be cost-effective if it could be conducted outside of work hours in a group setting. A subcommittee of the CDC’s Advisory Committee on Immunization Practices noted that universal influenza immunization for children would save money only if the total costs were less than $20 to $25 per child.

Logistic problems involved in the widespread administration of the influenza vaccine to children include the vaccine’s limited availability, the relatively small window of opportunity for vaccine administration, and the need for multiple injections, which are likely to be unacceptable to practitioners, parents, and children. Some medical practices may not be able to meet the seasonal time demands that would arise with a universal immunization program, and evening or weekend group vaccination clinics may not be feasible in all cases.

ANTIVIRAL DRUGS

The antiviral drugs amantadine and rimantadine can inhibit the replication of influenza A and, given prophylactically, can prevent 70% to 90% of illness. Amantadine is licensed for use in children beginning at age 12 months, but rimantadine is licensed for use only in children 13 years and older. Both drugs decrease the severity of influenza and shorten its duration by about one day.

The disadvantages of these antiviral agents are their lack of activity against influenza B, the possibility of the emergence of a resistant influenza strain, and adverse effects.

A new class of antiviral drugs that are active against both types A and B influenza includes zanamivir and oseltamivir. Zanamivir can be used to treat children 7 years and older, and oseltamivir can be used to treat children 12 months and older and as prophylaxis in children 13 years and older. The AAP’s Committee on Infectious Diseases stresses that “antiviral drugs are an adjunct to, not a substitute for, the prevention of influenza with immunization.”[1] However, they are indicated for prevention of influenza infection under certain circumstances (see Table 1).

Table 1 Indications for Antiviral Drugs as Prophylaxis

• To protect high-risk children during the two weeks following immunization if the child is immunized after influenza has begun circulating. • To protect high-risk children unable to receive the trivalent inactivated influenza vaccine. • To protect nonimmunized close contacts of high-risk children. • To protect immunocompromised children who may not respond to the trivalent inactivated influenza vaccine. • To control outbreaks of influenza in closed settings. • To protect immunized high-risk patients if the vaccine is not well matched to the circulating influenza strains for that year.

Data extracted from Pediatrics. 2002.[1]

—Gale Jurasek

Reference
1. Committee on Infectious Diseases Policy Statement. Reduction of the influenza burden in children. Pediatrics. 2002;110:1246-1252.

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