Immunological Shield Wavers with Age

The Elderly Display a Weaker Vaccine-Triggered Immune Response

Janet E. McElhaney, MD
Associate Professor, Division of Geriatrics,
Glennan Center for Geriatrics and Gerontology

Pneumonia and influenza together have been identified as a leading cause of catastrophic disability and the fourth leading cause of death in the age 65 and over population. The fact that older people have an increased risk of contracting influenza and/or pneumococcal disease is to a large extent due to the combination of immuno-senescence and chronic diseases affecting 80 to 90% of the over 65 population. The aging process results in a decline in immunity that largely affects T-cell-mediated defense mechanisms. In older people, this decline is associated with an increased risk of viral infections, particularly influenza. Humoral immunity may also diminish with aging but to a lesser degree, perhaps due to the T-cell function that regulates the production of antibodies. Due to their ability to stimulate the aging immune system, influenza and pneumococcal vaccinations are by far the most cost-effective medical interventions when it comes to older adults.

Impact of Influenza and Pneumococcal Infections
The association between advanced age and the risk of serious influenza infections is one of the most well-documented examples of the potential effects of immunosenescence.