Pneumococcal polysaccharide vaccine prevents mortality after pneumonia in adults aged 60 – 79 years – a Population-based cohort study in more than 738.000 adults over 60 years

Objectives:

The 23-valent pneumococcal polysaccharide vaccine (PPV) is recommended for prevention of pneumococcal diseases in adults at risk. Few data exist on time- age- and sex-dependent vaccine effectiveness on outcomes in pneumonia.

Methods:

We performed a population based cohort study including adults ≥60 years of age (n = 738,927) based on statutory health insurance data 2005 – 2011. Primary outcomes were all-cause pneumonia incidence and 30-day all-cause mortality. Pneumonia was identified via ICD-10 codes, ambulatory cases validated by antibiotic prescription within 7 days. The effect of PPV within 5 years was analyzed after propensity score based matching including comorbidities, care status, age, sex, and influenza vaccination. Evaluations were stratified by age group, sex and time of PPV.

Results:

Two-year incidence of all-cause pneumonia in 213,431 vaccinated individuals was 3.51% versus 3.63% in matched controls (difference -0.11, 95%CI -0.22 – 0.002, p = 0.046). After sex-dependent analysis, PPV effectiveness on pneumonia incidence was observed only in females (p = 0.02 for effectiveness). 30-day mortality in 7501 vaccinated individuals with pneumonia was 17.36% versus 18.96% in matched controls (difference -1.60%, 95%CI -2.83 – 0.38, p = 0.011). After analysis according to age group, significant mortality reduction was present only in adults of 60 to 79 years (p = 0.002 for effectiveness). Year of PPV vaccination showed no effect on outcomes.

Conclusions:

The findings support consideration of sex- and age-dependence of PPV effectiveness for vaccination recommendations.