Abstract: AIM: To assess the effectiveness of 23-valent penumococcal polysaccharide vaccine (PV) and influenza vaccine (IV) for preventing acute exacerbation in older patients with chronic lung diseases (CLD). METHODS: An open-label, randomized, controlled study among 192 older patients with CLD in a stable condition over a 1-year period was designed. Subjects were randomly assigned to a PV+ IV group (n=97) or an IV group (n=95). On base line survey, both groups were followed up one year about the time to the first episode of acute exacerbation after the enrollment in this study. RESULTS: The number of older patients with CLD experiencing infectious acute exacerbation(χ²＝6.659,P=0.010), but not death(χ²＝0.597,P=0.440), was significantly lower in the PV+ IV group compared with the IV group. In older patients with CLD, the Kaplan-Meier survival curves demonstrated a significant difference for infectious acute exacerbation(log-rank test,χ²＝8.065,P=0.005) between the two groups. CONCLUSION: This study demonstrated an additive effect of PV in combination with IV on infectious acute exacerbation of older patients with CLD.

Key words: 23-valent penumococcal polysaccharide vaccine, Influenza vaccine, Elderly, Chronic lung diseases, Acute exacerbation