New flu vaccination essential even though formulation didn't change

September 8, 2011

The influenza vaccine?s formulation may be unchanged from last year, but immunity in children can decline precipitously without another dose this year, according to new recommendations. The good news is that kids aged 6 months to 8 years need only 1 dose if they were vaccinated last year; others in that age group will still require 2 doses. Find out what else the new recommendations have to say, especially about immunization for youngsters with egg allergies.

Children’s immunity declines up to 50% in the 6 to 12 months after an influenza vaccination, making immunization before the October start of the flu season as important as ever-even though children vaccinated last year received the same combination recommended for this flu season, according to recommendations from the American Academy of Pediatrics (AAP).

The recommendations, however, include good news for children vaccinated last year and for pediatricians who have to administer the vaccine to unhappy recipients. Children aged 6 months to 8 years who were vaccinated during the 2010-2011 flu season need only 1 dose of vaccine instead of the 2 doses at least a month apart recommended for those who were not immunized last year.

Children and adolescents aged 9 years and older need just 1 dose, regardless of previous immunization. No influenza vaccines are approved for infants younger than 6 months old.

The AAP recommends universal vaccination for everyone older than 6 months, with particular attention to children younger than 5 years and those with high-risk conditions such as asthma, diabetes mellitus, neurologic disorders, sickle cell anemia, renal dysfunction, or immunosuppression.

Influenza generates up to 29% of emergency department visits for children aged between 2 and 5 years and caused 114 pediatric deaths last year, according to the federal Advisory Committee on Immunization Practices (ACIP). Influenza-associated hospitalization is most common in children younger than 2 years; in half of hospitalized children, no known underlying conditions exist, according to AAP.

In a change from previous years, based on recent data indicating that influenza vaccine administered in a single, age-appropriate dose is well tolerated by nearly all recipients who are allergic to eggs, AAP no longer recommends that children who have a mild allergic response, such as hives alone, undergo skin testing before immunization or split-dose immunization.

Instead, ACIP advises observing these patients for a reaction for 30 minutes after vaccination. Because studies on the response of egg-allergic persons to the influenza vaccine have been done using only the injectable trivalent inactivated vaccine (TIV), it should be used for children with mild egg allergies rather than the live-attenuated influenza vaccine (LAIV) delivered as a nasal spray.

Those with severe responses that require epinephrine or cause cardiovascular changes or respiratory or gastrointestinal symptoms should not be immunized before consultation with an allergist, according to the recommendations.

The Vaccine Adverse Event Reporting System has noted an elevated occurrence of febrile seizures in children aged between 12 and 23 months who received the influenza vaccine; all the affected children fully recovered. AAP and ACIP do not recommend prophylactic use of antipyretics in this age group because they do not reduce the occurrence of febrile seizures.

AAP recommends that pediatricians consider offering flu vaccines to parents and other caregivers “at the same time and in the same office setting as children.” If pediatricians extend vaccination opportunities to adults, priority should be given to household contacts and child care providers for high-risk children and those younger than 5 years, health care personnel, and pregnant or lactating women. The policy statement notes that infants of immunized women have better influenza-related health outcomes and may be less likely to be born prematurely.

TIV is approved for children and adults aged 6 months and older. LAIV is approved for healthy, nonpregnant persons aged 24 months and older.

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