PPV23 did not reduce death or readmission rates in high-risk patients

The 23-valent pneumococcal polysaccharide vaccine failed to reduce the 5-year rates of death or re-hospitalization in patients previously hospitalized with community-acquired pneumonia, according to recently published findings.

The population-based study was conducted among 2,950 patients hospitalized with community-acquired pneumonia between 2000 and 2002 in Canada.

The aim of the study was to determine the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) in preventing pneumonia — and not just rare instances of invasive pneumococcal disease — among patients who have survived an episode of hospitalization for community-acquired pneumonia.

The vaccine was administered to 956 patients, 70% of whom received it before they were hospitalized and 30% of whom received it during hospitalization.

Within 5 years of being discharged, 1,404 (48%) patients died and 504 (17%) were readmitted with a vaccine-preventable disease. The recurrent infection was pneumonia in 94% of cases. Overall, 1,626 (55%) patients died or were readmitted within 5 years, according to the results.

Receiving PPV23 was not associated with reduced risk or death or readmission. Overall, 62% of vaccinated patients were readmitted or died vs. 52% of the unvaccinated patients (HR=0.91; 95% CI, 0.79-1.04). These results were not altered upon further analysis using propensity scores, restricting the sample to patients 65 years or older or considering only patients who received the vaccine at discharge, according to findings.

The researchers said the vaccine may have failed to generate a sustained antibody response.

Johnstone J. Clin Infect Dis. 2010;51:15-22.