Respiratory viral infections in the elderly

Abstract

Viral respiratory infections represent a significant challenge for those interested in improving the health of the elderly. Influenza continues to result in a large burden of excess morbidity and mortality. Two effective measures, inactivated influenza vaccine, and the antiviral drugs rimantadine and amantadine, are currently available for control of this disease. Inactivated vaccine should be given yearly to all of those over the age of 65, as well as younger individuals with high-risk medical conditions and individuals delivering care to such persons. Live, intranasally administered attenuated influenza vaccines are also in development, and may be useful in combination with inactivated vaccine in the elderly. The antiviral drugs amantadine and rimantadine are effective in the treatment and prevention of influenza A, although rimantadine is associated with fewer side-effects. Recently, the inhaled neuraminidase inhibitor zanamivir, which is active against both influenza A and B viruses, was licensed for use in uncomplicated influenza. The role of this drug in treatment and prevention of influenza in the elderly remains to be determined. Additional neuraminidase inhibitors are also being developed. In addition, to influenza, respiratory infections with respiratory syncytial virus, parainfluenza virus, rhinovirus, and coronavirus have been identified as potential problems in the elderly. With increasing attention, it is probable that the impact of these infections in this age group will be more extensively documented. Understanding of the immunology and pathogenesis of these infections in elderly adults is in its infancy, and considerable additional work will need to be performed towards development of effective control measures.

Fig. 1

Rates of serologically documented influenza infection in adults over 60 randomized to receive inactivated influenza vaccine or placebo (data from Govaert et al., 1994).

Fig. 2

Rates of laboratory-documented influenza illness, outbreak-associated respiratory illness, and outbreak-associated influenza-like illness in nursing home residents randomized to receive parenteral inactivated influenza vaccine with intranasal cold-adapted influenza vaccine or intranasal placebo (from Treanor et al., 1992).

Fig. 3

Pre-illness levels of serum neutralizing antibody to group A RSV in elderly individuals enrolled in adult day care who were or were not subsequently infected with RSV during RSV outbreaks (from Falsey et al., 1995b).