Replacing PCV7 with universal childhood PCV13 immunization resulted in declining incidence of invasive pneumococcal disease and all-cause pneumonia in US adults; however, the decline was attenuated with increasing age and in those with comorbidities. This according to a retrospective study that evaluated the impact of replacing PCV7 with PCV13 on disease burden in adults and identified age/risk-specific subgroups with highest remaining disease burden. Study population included adults aged ≥18 years, stratified by age (18-49, 50-64, 65-74, and ≥75) and risk profile (healthy, at-risk, high-risk). Rate ratios comparing invasive pneumococcal disease (IPD), all-cause hospitalized pneumonia (ACHP), and pneumococcal pneumonia requiring hospitalization among at-risk and high-risk adults vs healthy counterparts, were estimated for 2007-2010 (pre-PCV13), 2011-2012 (peri-PCV13), and 2013-2015 (post-PCV13). Researchers found:
- IPD and ACHP rates increased with age and comorbidity across study periods.
- IPD rates declined 5-48% and ACHP rates declined 4-19% across age and risk groups from pre- to post-PCV13 period.
- The decline in IPD and ACHP was attenuated among older adults and those with comorbidities.
Pelton S, Bornheimer R, Doroff R, Shea KM, Sato R, Weycker D. Decline in pneumococcal disease attenuated in older adults and those with comorbidities following universal childhood PCV13 immunization. [Published online ahead of print September 20, 2018]. Clin Infect Dis. doi:10.1093/cid/ciy800.
This study highlights 2 concepts. It demonstrates immunosenescence—the gradual deterioration of the immune system by natural aging. The PCV13 vaccine showed decreasing efficacy in patients as they aged, as many other vaccines do. It also showed the efficacy of the conjugated pneumococcal vaccine and did show that covering more serotypes did protect more patients against bacteremia and pneumonia. —John Russell, MD