1427. A Dynamic Modeling Study of the Effect of Introducing a New Higher Valent Pneumococcal Conjugate Vaccine in a Paediatric Population in the United States

BACKGROUND: Routine use of pneumococcal conjugate vaccines (PCVs) in young children has substantially reduced vaccine-type invasive pneumococcal disease (IPD) in the United States and Europe. However, increases in disease and colonization caused by nonvaccine serotypes have been observed, suggesting the need for new PCVs with broader serotype coverage. The aim of this study was to estimate the population-level impact of new PCVs to replace the existing 13-valent vaccine (PCV13) in infants. METHODS: An age-structured dynamic transmission model of Streptococcus pneumoniae before and after PCVs introduction was developed. The model was fit to longitudinal Active Bacterial Core surveillance (ABCs) data (1997–2015) in the United States on distribution and cases of IPD, as well as population level prevalence and serotype distribution data. It was assumed that total S. pneumoniae carriage remains constant over time, with full carriage replacement within four years of introduction of any PCV. Two alternative new PCVs with differing IPD coverage are tested with an introduction date of 2024. RESULTS: When compared with continuing vaccination of infants with PCV13, 10 years after a new PCV is introduced (2,034) cases of IPD are substantially reduced (shown in the table below). Broader serotype coverage leads to greater reductions in IPD. The greatest IPD reduction occurs in the directly vaccinated infant groups, however similar reductions are also observed in the unvaccinated elderly population due to herd protection. CONCLUSION: A new, higher valent PCV given to infants in the United States has the potential to reduce future cases of IPD. Vaccination of infants may also have a substantial indirect benefit on IPD cases in adults and the elderly. DISCLOSURES: M. Madin-Warburton, Sanofi Pasteur: Consultant, IQVIA received consultancy fee. A. B. Pitcher, Sanofi Pasteur: Consultant, IQVIA received consultancy fee. M. H. Kyaw, Sanofi Pasteur: Employee, Salary. A. Kieffer, Sanofi Pasteur: Employee, Salary.