Heterogeneity of the efficacy of the 23-valent pneumococcal polysaccharide vaccine caused by various underlying conditions of chronic pulmonary disease in older patients: prospective cohort study.
OBJECTIVE
To determine the ideal conditions for use of the 23-valent pneumococcal polysaccharide vaccine (PPV23) in older outpatients with chronic pulmonary diseases.


METHODS
Prospective cohort study.


METHODS
1378 outpatients with chronic pulmonary diseases ≥ 60 years of age.


METHODS
Participants were educated about PPV23, and those who responded affirmatively were vaccinated between August and November 2002. The participants who chose no intervention served as controls. The prevaccine period was defined as August 2001 to August 2002. Participants were followed for 2 years from December 2002 or until death.


METHODS
Events of interest included the first episode of bacterial (including pneumococcal) pulmonary infection (primary endpoint) and death of any cause (secondary endpoint).


RESULTS
Frequent episodes of pulmonary infection during the prevaccine period significantly decreased event-free survival during the 2-year observation period (p<0.001). Chronic respiratory failure was associated with a decreased event-free survival only when the pulmonary infection episode did not occur in the prevaccine period (p<0.001). No significant differences in event-free survival were observed between the vaccinated and unvaccinated group during analysis of the entire cohort. In the Cox proportional hazards regression model, event-free survival decreased significantly when pulmonary infection occurred in the prevaccine period. In the subgroup analysis, the first episode of bacterial pulmonary infection (but not death of any cause) was reduced significantly by PPV23 only in patients with chronic respiratory failure who had no episodes of pulmonary infection during the prevaccine period (p=0.019).


CONCLUSIONS
The efficacy of PPV23 against pulmonary infection and death of any cause might be unachievable if pulmonary infection occurs during the prevaccine period. PPV23 needs to be given to older patients with chronic pulmonary disease at an earlier time in which infectious complications in the lung have not yet occurred.
Department of Epidemiology and Public Health and Department of Clinical Research, Yokohama City University Graduate School of Medicine, Yokohama, Japan. ino999@yokohama-cu.ac.jp
Satoshi
S
Inoue
Yuji
Y
Watanuki
Tetsuji
T
Kaneko
Takashi
T
Sato
Naoki
N
Miyazawa
Takeshi
T
Kaneko
Yoshiaki
Y
Ishigatsubo
Satoshi
S
Morita
Yutaka
Y
Natsumeda
Shunsaku
S
Mizushima