Evaluating the clinical effectiveness of pneumococcal vaccination in preventing myocardial infarction: The CAPAMIS study, three-year follow-up

Background: Cardiovascular benefits using the 23-valent pneumococcal polysaccharide vaccine (PPV23) are controversial. This study assessed clinical effectiveness of PPV23 in preventing acute myocardial infarction in people over 60-years.

Methodology: We conducted a population-based cohort study involving 27,204 individuals ≥60 years-old in Tarragona, Spain, who were prospectively followed from 01/12/2008 until 30/11/2011. Outcomes were hospitalization for AMI, 30-day mortality from AMI and all-cause death. Cox regression was used to evaluate the association between pneumococcal vaccination and the risk of each outcome.

Results: Cohort members were followed for a total of 76,033 person-years, of which 29,065 were for vaccinated subjects. Overall, 359 cases of AMI, 55 deaths from AMI and 2465 all-cause deaths were observed. Pneumococcal vaccination did not alter the risk of AMI (multivariable hazard ratio [HR]: 0.95; 95% confidence interval [CI]: 0.76-1.18; p=0.630), death from AMI (HR: 1.32; 95% CI: 0.76-2.28; p=0.321) and all-cause death (HR: 0.97; 95% CI: 0.89-1.05; p=0.448). In analyses focused on people with and without history of prior coronary artery disease, pneumococcal vaccination did not emerge effective in preventing any analyzed event.

Conclusions: This study supports that PPV23 does not provide any relevant benefit against AMI in the general population over 60 years, as in primary as well as in secondary prevention, although it is underpowered to exclude a small benefit of vaccination against rare outcomes.