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BMC Med
. 2023 Mar 22;21(1):106.
doi: 10.1186/s12916-023-02830-w.
Potential health and economic impact of paediatric vaccination using next-generation influenza vaccines in Kenya: a modelling study
Naomi R Waterlow 1 , Sreejith Radhakrishnan 2 3 , Jeanette Dawa 4 5 , Edwin van Leeuwen 2 6 , Simon R Procter 2 , Philipp Lambach 7 , Joseph Bresee 8 , Marie Mazur 9 , Rosalind M Eggo 2 , Mark Jit 2
Affiliations
- PMID: 36949456
- PMCID: PMC10032252
- DOI: 10.1186/s12916-023-02830-w
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.
Keywords: Cost-effectiveness; Health economics; Influenza; Mathematical modelling; Next-generation vaccines; Vaccination.