Influence of Aging and Immune Alterations on Susceptibility to Pneumococcal Pneumonia in the Elderly.

Pneumonia is a common respiratory infection affecting individuals of all ages, with a significantly higher incidence among the elderly. As the aging population grows, pneumonia is expected to become an increasingly critical health concern. In non-institutionalized elderly individuals, the annual incidence ranges from 25 to 44 per 1000, approximately four times higher than in those under 65. Streptococcus pneumoniae, a Gram-positive diplococcus, is the leading cause of pneumonia-related deaths in older adults. Management of S. pneumoniae infections in the elderly is challenging due to impaired antibody responses to polysaccharides and surface proteins, compounded by rising antibiotic resistance. The underlying mechanisms for increased susceptibility remain unclear, but age-related changes in the immune system, particularly in dendritic cells and T cells, are implicated. This review explores how aging-related immune alterations contribute to the heightened vulnerability of the elderly to S. pneumoniae infections.