Effectiveness and safety of dual influenza and pneumococcal vaccination versus separate administration or no vaccination in older adults: a meta-analysis

<b>Background:</b> The advantages of dual pneumococcal and influenza vaccination in older adults have not been clarified and controversy remains regarding their optimal use. <b>Methods:</b> This meta-analysis was conducted on 25 January 2018 using PubMed, the Cochrane Library, and Embase databases. Seventeen studies were selected ultimately for meta-analysis using a multi-step approach by two separate authors. Primary outcomes were pneumonia, pneumococcal pneumonia, influenza, hospitalization, and all-cause mortality rates, and the secondary outcome was adverse effects (AEs). <b>Results:</b> The additive preventive effects of dual influenza and pneumococcal vaccination versus influenza vaccination alone for pneumonia and death were 15% (95% confidence interval [CI]: 4-24%) and 19% (95% CI: 6-30%), respectively. Compared with pneumococcal vaccination alone, dual influenza and pneumococcal vaccination resulted in a 24% (95% CI: 16-31%) reduction in pneumonia and a 28% (95% CI: 13-40%) reduction in death. Compared with placebo or no vaccination, the effectiveness of dual vaccination was 29% (95% CI: 14-42%) for pneumonia, 38% (95% CI: 25-49%) for death, 35% (95% CI: 22-46%) for influenza, and 18% (95% CI: 6-29%) for hospitalization. Both vaccines showed acceptable safety profiles and AEs were mild or moderate. <b>Conclusion:</b> Our findings highlight the importance of concomitant influenza and pneumococcal vaccination in older adults.