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Epidemiologic Notes and Reports Prevention and Control of Influenza

Influenza viruses have continually demonstrated the ability to cause major epidemics of respiratory disease and frequently infect individuals who, because of their advanced ages and/or chronic underlying health conditions, are poorly able to cope with the disease. Excess deaths attributable to pneumonia and influenza are often documented during epidemics, and over 80% of these deaths occur among persons 65 years of age or older. Although annual influenza vaccination has long been considered the single most important measure in the prevention or attenuation of influenza virus infections, immunization surveys have repeatedly demonstrated that only about 20% of persons at high risk for influenza-related complications are vaccinated in any given year (1). In view of this observation, the Immunization Practices Advisory Committee (ACIP) recently reclassified the broadly defined high-risk group on the basis of priority, so that special efforts can be directed at providing influenza vaccine to persons who would derive the greatest benefit (2). These groups, in order of priority, are:

  1. Adults and children with chronic disorders of the cardiovascular or pulmonary systems that are severe enough to have required regular medical follow-ups or hospitalization during the preceding year; and residents of nursing homes and other chronic-care facilities.

  2. Physicians, nurses, and other personnel who have extensive contact with high-risk patients.

  3. Otherwise healthy individuals over 65 years of age; and adults and children with chronic metabolic diseases (including diabetes mellitus), renal dysfunction, anemia, immunosuppression, or asthma severe enough to require regular medical follow-up or hospitalization during the preceding year. Since there is considerable overlap in the target groups for

influenza and pneumococcal vaccination, physicians should consider giving both vaccines simultaneously at separate anatomical sites. However, in contrast to influenza vaccine, which should be administered annually, pneumococcal vaccine should be given only once (3). Providing detailed immunization records to each patient would help ensure that additional doses of pneumococcal vaccine are not given.

The ACIP also encourages physicians to administer vaccine to any persons in their practices who wish to reduce their chances of acquiring influenza infection and has also recommended amantadine hydrochloride prophylaxis and therapy when appropriate circumstances arise. Details concerning these and other aspects of influenza control have been published elsewhere (2). Reported by Div of Immunization, Center for Prevention Svcs, Influenza Br, Div of Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: Effective influenza vaccination programs require planning well in advance and should be completed, whenever possible, before the beginning of the influenza season. Although the earliest laboratory-confirmed cases of influenza are often documented in October, in recent years, peak activity has only rarely occurred before January. In most years, therefore, influenza vaccine can be administered from mid-October through December; if it is given much earlier, protection may be waning when there is still widespread influenza activity. It should also be emphasized, however, that the vaccine can be given until the time influenza viruses are isolated from patients in the local community, and thereafter, although temporary chemoprophylaxis with amantadine may be indicated (2).

Twenty-one states and Chicago, New York City, and the District of Columbia are providing influenza vaccine to high-risk groups on an annual basis. Funding sources for these activities vary considerably, ranging from fee systems to special appropriations by the state legislature. To supplement these efforts, CDC has expanded its activities to improve vaccination rates among adults, especially in those targeted to receive influenza and pneumococcal polysaccharide vaccines. These CDC activities will include educational programs for patients and medical-care personnel, surveillance activities, and evaluations of the organization, implementation, and outcome of vaccination programs in hospitals and other settings.


  1. CDC. U.S. immunization surveys (annual).

  2. ACIP. Prevention and control of influenza. MMWR 1985;34:261-8, 273-5.

  3. ACIP. Update: pneumococcal polysaccharide vaccine usage--United States. MMWR 1984;33:273-6, 281.

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