Research Information System
BMC Geriatrics, vol.26, no.1, 2026 (SCI-Expanded, SSCI, Scopus)
Background : Pneumonia remains a leading cause of morbidity and mortality in older adults, particularly due to the age-related decline in immune function. The aim of this study was to evaluate the association between frailty, malnutrition, and the severity of pneumonia in older adults who received the 13-valent pneumococcal conjugate vaccine (PCV13). Methods: A retrospective analysis was made of 407 geriatric outpatients aged over 65 years who had received PCV13. Clinical and radiological data were collected from electronic health records and verified via telephone interviews. The primary outcomes were incidence and severity of pneumonia (mild vs. severe), hospitalization, mortality, and antibiotic use within one year following vaccination. Pneumonia severity was classified according to established criteria in the literature. Results: Of the 407 patients evaluated (mean age 73.3 ± 6.3 years; range 65–91 years; 62.9% female), 50 (12.2%) developed pneumonia within one year after PCV13 vaccination. Pneumonia was more common in patients with diabetes mellitus (p = 0.003) and chronic obstructive pulmonary disease (p < 0.001). Severe pneumonia was significantly more prevalent among frail individuals (p = 0.006). Compared to patients with mild pneumonia, those with severe pneumonia had higher Clinical Frailty Scale scores and prolonged chair stand test durations (p = 0.002 and p = 0.031, respectively). After adjusting for age, sex, and frailty, malnutrition emerged as an independent risk factor for severe pneumonia (OR: 11.9, 95% CI: 1.592–89.285, p = 0.016). Conclusion: The findings of this study indicate that malnutrition and frailty are independent risk factors for severe pneumonia diagnosed within a year of PCV13 vaccination in older adults. Consequently, comprehensive geriatric assessment and targeted interventions beyond vaccination are essential to reduce pneumonia risk in frail or malnourished older populations. Trial registration: Not applicable.