Influenza Vaccine Guidelines
According to the Advisory Committee on Immunization Practices (ACIP), influenza vaccination is currently recommended for all persons 50 years of age or older, all children between 6 months and 18 years of age, and persons 19 to 49 years of age who have underlying medical conditions, are pregnant, are employed as health care workers, or are household contacts of high-risk persons (a group that includes all children in the household who are younger than 5 years of age). Infants younger than 6 months of age, who have the highest hospitalization rates, although ineligible for vaccination, can be protected by immunization of their mothers during pregnancy.
The older adamantanes, amantadine, and rimantadine are currently not recommended for use in the United States because almost all influenza A (H3N2) viruses are resistant to them, and they are not effective against influenza B viruses. When influenza A (H1N1) viruses predominate, however, these drugs may still be useful if they are used in combination with a neuraminidase inhibitor. An increasing proportion of influenza A (H1N1) viruses are resistant to oseltamivir, the oral neuraminidase inhibitor, but not to zanamivir. Zanamivir is a neuraminidase inhibitor that is administered by active inhalation, a method that may not be practical for debilitated patients or for children younger than 7 years of age, and is contraindicated in those with reactive airway disease.
New England Journal of Medicine - Vol. 359, No. 24, December 11, 2008