Serotype-specific incidence and comparative vaccine coverage of invasive pneumococcal disease among adults ≥65 years of age in European countries from 2011 to 2023

BACKGROUND: Invasive pneumococcal disease (IPD) is associated with a significant clinical and economic burden among adults ≥65 years of age in Europe. The distribution of bacterial serotypes responsible for IPD has changed over time, including in response to the introduction of pediatric and adult pneumococcal conjugate vaccines (PCVs). These shifts necessitate the ongoing development of new multivalent vaccines to ensure that pneumococcal vaccination programs continue to target serotypes associated with significant disease burden. OBJECTIVE: The aim of the current study was to compare the proportion of IPD cases among adults ≥65 years of age that are targetable with PCV21 compared to PCV20 in multiple European countries, and to assess trends in these proportions over time. METHODS: We synthesized age- and serotype-specific IPD incidence data from 2011 to 2023. Data were obtained from government surveillance reports and peer-reviewed publications. RESULTS: Continuous serotype-specific data on the incidence of IPD among adults ≥65 years of age were available for 15 European countries. The average proportion of these IPD cases that were targetable by PCV21 increased during the study period; from 2014 onward, this proportion exceeded the proportion of cases targetable by PCV20, with an overall difference in serotype coverage of 14.0 % by 2023. These trends were driven largely by 8 countries that had a markedly higher reported incidence of IPD between 2011 and 2019 compared to the other 7 countries. CONCLUSIONS: In many European countries, PCV21-targetable serotypes are now responsible for more cases of IPD among adults ≥65 years of age than are PCV20-targetable serotypes. Implementing PCV21 in adult pneumococcal vaccination programs may therefore help reduce the clinical and economic burden of IPD among this high-risk age group.