than 20,000 excess deaths from influenza in the United States, 80 to 90 percent of which occur among the elderly. Influenza can lead to such complications as pneumonia, both viral and bacterial, and cardiac respiratory failure. It can also aggravate preexisting conditions such as diabetes or asthma. Lengthy periods are needed to recover from influenza.

Morbidity and mortality from influenza are largely unnecessary because effective preventive measures in the form of safe, effective vaccines became available in the late 1960s. Modern vaccines are trivalent, with two type A and one type B strains, and contain egg-grown viruses. (Vaccines are contraindicated in persons allergic to eggs.) All current influenza vaccines contain only inactivated (killed) viruses and must be given every year because of changing viruses and declining antibody levels. In field studies, vaccines have proven to be approximately 70 percent effective in preventing influenza illness, with the remaining 30 percent of vaccinees suffering a milder illness than that acquired by unvaccinated persons. Vaccines are effective in elderly persons living in the community24,27 as well as those in long-term care,38,39 although they are less immunogenic in the immunosuppressed elderly. For immunized immunosuppressed persons and for persons unable to take vaccines, antiviral prophylaxis or treatment (or both) with amantadine is effective against influenza A strains.2 However, vaccines are the only protection against type B influenza viruses. Influenza vaccine can be effectively given even during an epidemic if the vaccinee is also given prophylactic doses of amantadine for the 14 days required for vaccine-induced antibodies to develop. The assurance factor for influenza vaccines and the antiviral amantadine is high.

The costs and benefits of influenza vaccine have been estimated. 30,31,54 Because vaccines, although safe and relatively inexpensive, must be given to millions of high-risk elderly each year, it was concluded that influenza vaccines were not cost-saving. They were considered cost-effective, nevertheless, because they produced substantial health benefits for low unit costs.30,31,54

The committee strongly endorses the use of influenza vaccine and, where indicated, amantadine for the elderly. Amantadine should be used as prophylaxis during epidemics for persons allergic to eggs. The committee also considers the recent Health Care Financing Administration (HCFA) initiative (to conduct pilot studies for determining whether Medicare should fund influenza immunization) to be a positive step. (Presumably, if the pilot studies can demonstrate cost reductions for Medicare claims, HCFA will deem influenza vaccine to be beneficial and affordable.) Furthermore, the



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