Management of Influenza in the Elderly
Rosaly Correa-de-Araujo, MD, MSc, PhD
Program Director, Geriatrics & International Health
American Society of Consultant Pharmacists

Clinical Tips
Disease Prevention Tips
Table 1- Influenza Chemoprophlaxis in the Elderly
Treatment Tips
Table 2 - Summary of Pharmacotherapy for Influenza in the Elderly
Under Investigation
References
Other Treatment Resources

Clinical Tips

• Epidemics of influenza occur during the winter months, with rates of serious morbidity and mortality being higher among persons aged > 65 (approximately 34 million in the United States) and persons of any age who have medical conditions that place them at high risk for complications from influenza.
  
  
• Influenza is the fourth leading cause of death among elderly individuals. Among elderly subjects, estimated rates (1972-1981) of influenza-related hospitalizations range from 200 to > 1,000 per 100,000 population.
  
  
• Abrupt onset of constitutional and respiratory signs and symptoms (e.g., fever, myalgia, headache, severe malaise, sore throat, rhinitis, and nonproductive cough) characterize the uncomplicated illness. In the elderly, however, the diagnosis of influenza can be difficult because typical clinical signs such as fever and cough may not be present.
  
  
• Resolution of the illness typically occurs after several days, but cough and malaise can persist for 2 or more weeks.
  
  
• Influenza can exacerbate underlying medical conditions (e.g., pulmonary or cardiac disease) or lead to secondary bacterial pneumonia or primary influenza viral pneumonia.

Disease Prevention Tips
Immunoprophylaxis

• Immunoprophylaxis with inactivated (i.e., killed-virus) vaccine is the principal means for reducing influenza-related morbidity and death. The effectiveness of this vaccine depends primarily on the age and immunocompetence of the recipient and the degree of similarity between the virus strains contained in the vaccine and those circulating in the environment.
  
  
• Vaccination is recommended for:
  • all individuals > 65 years old (especially residents of nursing homes and other chronic-care facilities)
  • persons who are clinically or subclinically infected and can transmit influenza:
  • physcians, nurses, other personnel in both hospital and outpatient settings
  • employees of nursing homes and chronic care facilities who have contact with patients and residents
  • employees of assisted living and other residences for persons in high risk group
  • persons who provide home care to persons in high risk groups
  • household members (including children) of persons in high risk groups
    
    
• Elderly patients should receive a single dose (0.50 mL) of the whole or split virus vaccine administered in the deltoid muscle.
  
  
• Among elderly persons residing in nursing homes, influenza vaccine is 50 to 60% effective in preventing hospitalization due to severe illness and/or secondary complications, and 80% in preventing death.
  
  
• Because elderly persons tend to develop lower post-vaccination antibody titers compared to healthy young adults, susceptibility to influenza-related upper respiratory tract infection may persist in these individuals.
  
  
• The potential benefits of influenza vaccination in preventing serious illness, hospitalization, and death outweigh the possible risks for developing vaccine-associated Guilan Barre syndrome. No evidence indicates that the case fatality ratio for such complication differs among vaccinated and not vaccinated elderly.
  
  
• Inactivated influenza vaccine should NOT be administered to elderly known to have anaphylactic hypersensitivity to eggs or to other components of the vaccine. In such patients, the use of antiviral agents (amantadine, rimantadine) is an option for preventing influenza A infection. For elderly individuals who have a history of anaphylactic hypersensitivity to vaccine components and are also at risk for complications of the disease, desensitization prior to administration of the vaccine, is recommended.

Chemoprophylaxis

• Chemoprophylaxis should be considered for the following persons:
  • Those at high risk who vaccinated after influenza A activtity has began. In this case, chemoprophylaxis should be administered from the time of vaccination until immunity has developed, which can take as long as 2 weeks.
  • Unvacinnated persons who provide care (e.g., household members, visiting nurses, volunteer workers and employees of hospitals, clinics, and chronic care facilities) to those at risk.
  • Vaccinated or unvaccinated persons who provide care to high risk persons when outbreak is caused by a variant strain of influenza A that might not be controlled by the vaccine.
    
    
• Adamantanes (amantadine, rimantadine) are indicated for prophylaxis of influenza A virus infection. Oseltamivir is indicated for prophylaxis of influenza A and B virus infections.
  
  
• To be maximally effective the selected drug must be taken each day for the duration of influenza activity in the community. To be most cost-effective the drug should be taken only during the period of peak influenza activity in the community. Influenza outbreaks frequently occur in nursing homes.
  
  
• When initiated before exposure (seasonal prophylaxis) amantadine and rimantadine are 70- to 90% effective in preventing influenza A infection. In a seasonal prevention study conducted in nursing homes, oseltamivir reduced the incidence of laboratory confirmed clinical influenza from 4.4% for the placebo group to 0.4% for the treatment group.
  

Table 1 summarizes information on influenza chemoprophylaxis in the elderly.

Table 1 - Influenza Chemoprophylaxis in the Elderly

General Measures to Limit Influenza Transmission in Institutions

• Isolation of symptomatic residents or staff, especially those under chemoprophylaxis
• Use of masks to prevent droplet transmission
• Educational programs addressing staff and residents on the benefits of preventive practices

Treatment Tips

• Influenza specific antiviral drugs - are an important adjunct , but NOT a substitute to vaccine.
  
  
• To reduce the emergence of antiviral drug-resistant viruses, treatment should be discontinued as soon as clinically improvement occur, generally 3 to 5 days of treatment or within 24-48 hours after disappearance of signs and symptoms.
  
  
• Adverse effects and emerging resistance patterns have limited the use of amantadine and rimantadine. There is no evidence showing that treatment with adamantanes reduces the incidence of complications or death in high-risk* patients
  
  
• Compared to the adamantanes, oseltamivir and zanamivir have better tolerance, less potential for emergence of resistance, but are a high cost therapy. Febrile laboratory confirmed influenza patients treated with oseltamivir within 36 hours of onset experienced a 30% reduction in the duration of illness and 38% reduction in the disease severity. Febrile laboratory confirmed influenza patients treated with zanamivir within 36 hours of onset of the disease, had the time to alleviation of clinically important symptoms shortened from 6.5 to 4.5 days. Also a reduced requirement for antibiotic therapy to treat secondary complications was observed in a group of high-risk patients (elderly included).

Table 2 - Summary of Pharmacotherapy for Influenza in the Elderly

*High-risk patients include those who are 65 years of age and over and have a compromised immune system or underlying respiratory, endocrine, metabolic, or cardiovascular disorders.

**Cost calculated from average wholesale prices as displayed in the 2000 edition of the Red Book

Under Investigation

• Neuraminidases are not currently approved for chemoprophylaxis in the United States. Efficacy, however, has been demonstrated in short-term (10-14 days) preventive studies. Their role in chemoprophylaxis is under investigation.
  
  
• Combination of zanamivir and vaccination is reported to result in shorter median time to alleviation of influenza symptoms compared to each agent alone.

References

• Abarca J, Krueger TS. Influenza: a practical review. JMCP 2000; 6(3): 247-8.
• Bowles SK, Kennie N, Ruston L, et al. Influenza outbreak in a long-term care facility: considerations for pharmacy. Am J Health-Syst Pharm 1999; 56: 2303-7.
• Centers for Disease Control and Prevention. Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Morttal Weekly Report 1999; 48(RR-4).
• Centers for Disease Control and Prevention. Neuraminidase inhibitors for treatment of influenza A and B infections. MMWR Morb Morttal Weekly Report 1999; 48(RR-14).
• Centers for Disease Control and Prevention. Prevention and control of vaccine-preventable diseases in long-term care facility. J Am Med Dir Assoc 2000; 15), Sep/Oct Supplement.
• Chapple KJ, Hendrick AE, McCarthy MW. Zanamivir in the treatment and prevention of influenza. Ann Pharmacother 2000; 34: 798-801.
• Drinka PJ, Gravenstein S. management of influenza in thje nursing jhome. Annals of long-Term Care: Clinical Care and Aging 2000; 8(9): 23-30.
• FDA Talk Paper. FDA approves tamiflu for another indication - prevention of influenza. Nov 20, 2000. http://www.fda.gov/bbs/topics/answers/ANS01056.html
• Gubareva LV, Kaiser L, hayden FG. Influenza virus neuraminidase inhibitors. Lancet 2000; 355: 827-35.
• Hayden FG, Atmar RL, Schilling M, et al. Use of the selective oral neuraminidase inhibitor oseltamivir to prevent influenza. NEJM 1999; 341: 1336-43.
• Keyser LA, Karl M, Nafziger AN, et al. Comparison of central nervous system adverse effects of amantadine and rimantadine used as sequential prophylaxis of influenza A in elderly nursing home patients. Arch Intern med 200; 160: 1485-88.
• McElhaney J. Neuraminidase inhibitors in the elderly and high-risk. Program and Abstracts of the Second International Symposium on Influenza and Other Respiratory Viruses. Grand Cayman, Cayman Islands, British West Indies. Dec 10-12, 1999.
• Monto a, gravenstein S. influenza prevention and treatment: a health imperative. Supplement to Nursing Home Medicine Dec. 1999.
• Nicholson KG, Aoki FY, Osterhaus ADME, et al. Efficacy and safety of oseltamivir in treatment of acute influenza: a randomized controlled trial. Lancet 200; 355: 1845-50.
• Treanor JJ, Hayden FG, Vrooman PS, et al. Efficacy and safety of the oral neuraminidase inhibitor oseltamivir in treating acute influenza. A randomized controlled trial. JAMA 2000; 283(8): 1016-24.
• Randomized trial of efficacy and safety of inhaled zanamivir in treatment of influenza A and B virus infections. The MIST (Management of Influenza in the Southern Hemisphere Trialists) Study Group. Lancet 1998; 352:1877-81.
• Schilling M, Povinelli L, et al. Efficacy of zanmivir for chemoprophylaxis of nursing home influenza outbreaks. Vaccine 1998; 16(18):1771-4.

Other Treatment Resources

Centers for Disease Control and Prevention, Influenza Prevention and Control home page

Centers for Disease Control and Prevention Report: Neuraminidase Inhibitors for Treatment of Influenza A and  B Infections

The above report on neuraminidase inhibitors is also available in Adobe Acrobat format.  Click here to download.

Advisory Committee on Immunization Practices Recommendations on Prevention and Control of Influenza 2000-2001.  (Adobe Acrobat file).

Note:  Many of the documents available on this web page are in Adobe Acrobat format (PDF files).  These files are best viewed with the latest version of the Adobe Reader software, available free on the Adobe web site.

Last updated: July, 2007.
For questions, please contact immunizations@ascp.com.