Association between pneumococcal vaccination and cardiovascular outcomes: a systematic review and meta-analysis of cohort studies

Aims Streptococcus pneumoniae is the most common cause of community-acquired pneumonia (CAP) and CAP-related mortality in adults. Pneumococcal vaccination (PV) could protect subjects from cardiovascular events by reducing pneumonia severity or even preventing it. We sought to determine the ability of PV to protect from the risk of cardiovascular events. Methods and results A comprehensive search of electronic databases was conducted up to March 2014. Cohort studies that reported relative risk (RR) estimates with 95% confidence intervals (CI) were included. Eleven studies were included (332,267 participants, mean follow-up 20.1 months). The pooled RRs for cardiovascular events and cardiovascular mortality were 0.86 (95% CI: 0.76-0.97) and 0.92 (95% CI: 0.86-0.98; fixed-effects), respectively, for subjects with PV versus without PV. Protective ability was more prominent in high cardiovascular risk populations and with older age. The protective role of PV was attenuated after 1 year (RR: 0.72; 95% CI: 0.59-0.88 vs RR: 1.03; 95% CI: 0.93-1.14; p=0.002, for follow-up >1 year vs 1 year, respectively). It also increased as the presence of cardiovascular and pulmonary disease increased. Regarding myocardial infarction (MI) and cerebrovascular events, the protective role of PV was statistically significant only in the elderly (RR: 0.90; 95% CI: 0.817-0.999; fixed-effects and RR: 0.86; 95% CI: 0.75-0.99, respectively). Conclusion PV is associated with decreased risk of cardiovascular events and mortality. This protective effect increases at older age and in high cardiovascular risk subjects and decreases as the time elapses from PV. PV decreases the risk of MI and cerebrovascular events in the elderly.