Abstract

BACKGROUND: Several higher-valent pneumococcal conjugate vaccines (PCVs) have been licensed recently, including a 20-valent PCV (PCV20) for children and adults and 21-valent PCV (aPCV21) licensed for adults. We assessed the potential for aPCV21 to further reduce the burden of invasive pneumococcal disease (IPD) in England. METHODS: IPD cases are electronically reported to the UKHSA and pneumococcal isolates are routinely submitted to the UKHSA national reference laboratory for confirmation and serotyping. We used national enhanced surveillance data for all IPD cases confirmed in England (July 2023-June 2024) to estimate the number of cases potentially preventable by aPCV21 in addition to the current childhood 13-valent PCV (PCV13) programme and a potential future childhood PCV20 programme. RESULTS: There were 5080 confirmed IPD cases. 4826 cases (95.0%) were serotyped, of which there were 1402 cases (29.1% of serotyped isolates) of PCV13-serotype IPD and 3105 cases (64.3%) of PCV20-serotype IPD, including 1703 cases (35.3%) with additional serotypes compared to PCV13. aPCV21 contains four shared serotypes with PCV13, seven additional serotypes shared with PCV20 and 10 novel serotypes. This equated to 939 (19.5%), 2642 (54.7%) and 1300 (26.9%) IPD cases with known serotype, respectively. Across England, 6.9% (271/3942) of aPCV21-serotype IPD cases were in children aged <15 years, 35.8% (1411/3942) in adults aged 15-64 years and 57.3% (2260/3942) in older adults aged ≥65 years. By age group, however, the proportions of IPD cases due to aPCV21 serotypes were similar and there were no significant differences in aPCV21 coverage by clinical presentation or fatal outcomes. CONCLUSIONS: aPCV21 has the potential to prevent a large proportion of the remaining IPD burden in adults. Given that the proportion of aPCV21-serotypes within age groups is similar, such a vaccine would have a large impact in the childhood immunisation programme because of the direct and indirect protection offered by the vaccine.