A Systematic Review of Studies Published between 2016 and 2019 on the Effectiveness and Efficacy of Pneumococcal Vaccination on Pneumonia and Invasive Pneumococcal Disease in an Elderly Population.

Adult vaccination is high on the agenda in many countries. Two different vaccines are available for the prevention of pneumococcal disease in adults: a 23-valent polysaccharide vaccine (PPV23), and a 13-valent conjugated vaccine (PCV13). The objective of this review is to update the evidence base for vaccine efficacy and effectiveness of PPV23 and PCV13 against invasive pneumococcal disease and pneumonia among an unselected elderly population. We systematically searched for clinical trials and observational studies published between January 1 2016 and April 17 2019 in Pubmed, Embase, Cinahl, Web of Science, Epistemonikos and Cochrane databases. Risk of bias was assessed using Cochrane Risk of Bias tool for and the Newcastle-Ottawa Scale. Results were stratified by vaccine type and outcome. We identified nine studies on PCV13 and six on PPV23. No new randomized clinical trials were identified. Due to different outcomes, it was not possible to do a meta-analysis. New high-quality observational studies indicate protective vaccine effectiveness for both vaccines against vaccine type pneumonia. Our estimates for the protective vaccine efficacy and effectiveness (VE) of PPV23 on pneumonia and pneumococcal pneumonia overlap with results from previously published reviews. Some of the results indicate that the effectiveness of the PPV23 is best in younger age groups, and that it decreases over time.