Serotype dynamics in pneumococcal diseases and the performance of vaccination strategies for older adults in germany

Objectives: In Germany, PPSV23 is recommended for the prevention of pneumococcal diseases (PD) in older adults. In 2016, a German modelling study showed that PCV13 was less effective and sequential vaccination (PCV13 + PPSV23; SEQ) not efficient due to major declines in PCV13-type PD. This study reevaluates the performance of pneumococcal vaccination strategies in older adults in Germany based on new available data. Methods: A dynamic transmission model of pneumococcal carriage was developed to predict the epidemiological impact of childhood PCV13-vaccination (indirect herd effects and serotype replacement) on the incidence and the serotype mix in PD among older adults. Vaccination strategies in older adults were evaluated in 48 scenarios. Results: Compared with pre-PCV levels, the model predicted reductions of 84% and 69% in PCV13-type invasive pneumococcal disease (IPD) and non-bacteremic pneumococcal pneumonia (NBPP). Non-PCV13-type PD incidence increased by 170% in IPD and 190% in NBPP. Depending on the scenario, a SEQ vaccination campaign in pneumococcal seasons 2020/2021-2029/2030 would gain 249-65,131 QALYs compared with PPSV23 and 3,958-17,152 compared with PCV13. At a threshold of 50,000 Euro per QALY gained, PPSV23 was the most cost-effective vaccination strategy in 25 scenarios, SEQ in 20 scenarios and PCV13 in 3 scenarios. At a threshold of 100,000 Euro per QALY gained, SEQ was economically preferable in 32 scenarios and PPSV23 in 16 scenarios. Conclusions: Vaccination of older adults against PD is highly effective and very likely to be cost-effective in Germany. From an economic perspective, PPSV23 or SEQ would be preferred to PCV13 only.