DB is 72 years old and recently moved into a nursing home. She has not received her yearly influenza shot. DB has numerous health problems, including diabetes mellitus, arthritis (for which she receives prednisone) and emphysema. She has a history of having influenza almost every year for the past 15 years.
1. The answers are A, B and C: her age, her residency in an institution and her chronic medical problems. Elderly persons and persons six months of age or older who are residents of chronic care facilities or who have certain chronic medical disorders (including cardiac, respiratory, renal or immunologic problems, hemoglobinopathies and diabetes) are at an increased risk for complications from influenza infection. Health care workers infected with influenza represent a potential vector for spread to high-risk patients. More than 90 percent of the deaths attributed to pneumonia and influenza in epidemics occur among persons 65 years of age and older.1
Influenza is estimated to cause a yearly average of 4.1 to 4.4 million excess respiratory illnesses and 16.6 to 17.9 million excess bed and restricted activity days in persons 20 years of age or older.2
Influenza infection can result in considerable morbidity and mortality. A study of influenza vaccination among community-dwelling elderly persons reported reductions of 48 to 57 percent for hospitalizations because of pneumonia and influenza, and reductions of 27 to 39 percent for all acute and chronic respiratory conditions.3
Reductions in morbidity, hospitalizations and mortality have also been reported in observational studies.
2. The answer is C: prophylaxis following exposure to influenza A. Amantadine and rimantadine are effective only against influenza A when used prophylactically in healthy community-living or institutionalized persons. Effectiveness is estimated to be 70 to 90 percent.4–6
Neither drug is effective for influenza B, so it is important to be knowledgeable about the likely type of influenza pathogen within the community. Either drug (200 mg per day) should be started at the time of influenza vaccination and continued for 14 days. Amantadine can also be used in unimmunized persons to enhance protection among those who may have a poor antibody response, or among those in whom the vaccine is contraindicated.
3. The answer is C: between October and mid-November. Because the influenza season in the United States usually begins in December, the period between October and mid-November usually is the optimal time for immunization campaigns. However, health care professionals should take advantage of the opportunity to begin immunizing all high-risk patients, including older adults, who are seen for health care beginning in September. Immunization programs may begin as soon as the current vaccine is available if regional influenza activity is expected to begin earlier than December. Immunization should be offered up to and even after the time that influenza virus activity is documented in a community. In some years, this activity may occur as late as April.
4. The answers are A, C and D: the influenza vaccine can be given concurrently with the pneumococcal vaccine; the influenza vaccine cannot cause influenza; and it is important not to give vaccines too early in the influenza season. The presence of minor illness, with or without fever, is not a contraindication to use of the influenza vaccine. However, adults with acute febrile illness should not be vaccinated until their symptoms have abated. The influenza vaccine should be given shortly before the onset of the influenza season. Because antibody levels decline with time, immunizations should not be given too early in the influenza season.