Potential health and economic impact of paediatric vaccination using next-generation influenza vaccines in Kenya: a modelling study

Waterlow, N. R., Radhakrishnan, S. , Dawa, J., van Leeuwen, E., Procter, S. R., Lambach, P., Bresee, J., Mazur, M., Eggo, R. M. and Jit, M. (2023) Potential health and economic impact of paediatric vaccination using next-generation influenza vaccines in Kenya: a modelling study. BMC Medicine, 21, 106. (doi: 10.1186/s12916-023-02830-w) (PMID:36949456) (PMCID:PMC10032252)

Abstract

Background: Influenza is a major year-round cause of respiratory illness in Kenya, particularly in children under 5. Current influenza vaccines result in short-term, strain-specific immunity and were found in a previous study not to be cost-effective in Kenya. However, next-generation vaccines are in development that may have a greater impact and cost-effectiveness profile. Methods: We expanded a model previously used to evaluate the cost-effectiveness of seasonal influenza vaccines in Kenya to include next-generation vaccines by allowing for enhanced vaccine characteristics and multi-annual immunity. We specifically examined vaccinating children under 5 years of age with improved vaccines, evaluating vaccines with combinations of increased vaccine effectiveness, cross-protection between strains (breadth) and duration of immunity. We evaluated cost-effectiveness using incremental cost-effectiveness ratios (ICERs) and incremental net monetary benefits (INMBs) for a range of values for the willingness-to-pay (WTP) per DALY averted. Finally, we estimated threshold per-dose vaccine prices at which vaccination becomes cost-effective. Results: Next-generation vaccines can be cost-effective, dependent on the vaccine characteristics and assumed WTP thresholds. Universal vaccines (assumed to provide long-term and broad immunity) are most cost-effective in Kenya across three of four WTP thresholds evaluated, with the lowest median value of ICER per DALY averted ($263, 95% Credible Interval (CrI): $ − 1698, $1061) and the highest median INMBs. At a WTP of $623, universal vaccines are cost-effective at or below a median price of $5.16 per dose (95% CrI: $0.94, $18.57). We also show that the assumed mechanism underlying infection-derived immunity strongly impacts vaccine outcomes. Conclusions: This evaluation provides evidence for country-level decision makers about future next-generation vaccine introduction, as well as global research funders about the potential market for these vaccines. Next-generation vaccines may offer a cost-effective intervention to reduce influenza burden in low-income countries with year-round seasonality like Kenya.

• Item Type: Articles
• Keywords: Research Article, Influenza, Vaccination, Cost-effectiveness, Mathematical modelling, Next-generation vaccines, Health economics
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Radhakrishnan, Dr Sree
• Authors: Waterlow, N. R., Radhakrishnan, S., Dawa, J., van Leeuwen, E., Procter, S. R., Lambach, P., Bresee, J., Mazur, M., Eggo, R. M., and Jit, M.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: BMC Medicine
• Publisher: BioMed Central
• ISSN: 1741-7015
• ISSN (Online): 1741-7015
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in BMC Medicine 21: 106
• Publisher Policy: Reproduced under a Creative Commons License