Immunizations - Viral Influenza

Antibodies to the flu virus usually develop within two weeks of vaccination, and immunity peaks within four to six weeks, then gradually wanes.

Because children under age nine do not develop strong immune responses to one dose, the CDC recommends two vaccinations given one month apart.
Early research also suggests that it may be equally effective to administer children?s vaccinations in the spring and fall, rather than one month apart; further study is ongoing.
It should be noted that if an individual develops flu symptoms and is accurately diagnosed in time, vaccination of the other members of the household within 36 ? 48 hours affords effective protection to those individuals, according to a 2004 Canadian analysis of multiple studies.

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In healthy adults, immunization typically reduces the chance of the flu by about 70 - 90%. The current flu vaccines may be slightly less effective in certain patients, such as the elderly and those with certain chronic diseases. Some evidence suggests, however, that even in people with a weaker response, the vaccine is usually protective against serious flu complications, particularly pneumonia. The major outstanding question is whether the vaccination prevents complications of serious illness. One 2003 study, for instance, reported no reduction in severity of chronic lung diseases among vaccinated patients with asthma, emphysema, or chronic bronchitis. Some evidence suggests, on the other hand, that among the elderly, a flu shot may help protect against stroke, adverse heart events, and death from all causes.

Candidates for the Flu Vaccine

Children Who Should Be Vaccinated. The following children over six months should be vaccinated against the flu:

The American Academy of Pediatrics (AAP) and the CDC recommend flu shots for all healthy children between 6 and 23 months of age. In addition, any child over the age of 2 years who has a condition that requires regular medical care or who has been hospitalized for a serious illness (particularly lung or kidney disease, diabetes, sickle-cell, or immune deficiencies).
Children who are receiving long-term aspirin therapy should also receive a flu shot. Children who get the fluare at higher risk for Reye''s syndrome, a life-threatening disease.
Some experts now advocateflu shots forall school-age children. Emerging research indicates that children are responsible for transmitting the vast majority of cases of the flu, and that routine vaccination of school-age children would considerably reduce transmission rates throughout communities.