Overcoming the challenges of immunosenescence in the prevention of acute respiratory illness in older people.

This article describes the impact of acute respiratory illness (ARI) and the challenges to primary prevention of viral ARI and related morbidity in the age 65 and older population. Immunosenescence, the immune system's "memory loss" with aging, compromises both host defense mechanisms against ARI and effective responses to vaccination. Atypical presentations of illness common in older people often lead to delayed or missed diagnoses of ARI and disabling consequences. Thus, preventing ARI will be more effective than treatment. Even with the limited efficacy of current influenza vaccines in older people, vaccination is a cost-saving intervention especially in high-risk groups including those with chronic heart or lung diseases. Significant opportunities to further reduce the morbidity of ARI include developing more effective influenza vaccines and vaccines against other ARI. Combining vaccination with antiviral or immunoenhancing agents particularly in high-risk groups could optimize the cost benefit of additional preventive strategies.