Universal influenza vaccines could prevent up to 3.0 billion infections and approximately 826,000 deaths annually, assuming annual vaccination of 50% of children younger than 18 years globally, according to a recent study.
Researchers conducted a comprehensive modeling analysis to evaluate the global health and economic impact of next-generation influenza vaccines (NGIVs). They assessed the cost-effectiveness of various NGIV strategies across 186 countries and territories using a dynamic age-structured transmission model and an economic evaluation framework.
The investigators, led by Lucy Goodfellow of the Department of Infectious Disease Epidemiology and Dynamics at the London School of Hygiene and Tropical Medicine, applied a four-step modeling process. This included: (1) epidemiological inference from WHO FluNet surveillance data, (2) simulation of future epidemics accounting for demographic changes through 2054, (3) vaccination modeling stratified by age and coverage, and (4) cost-effectiveness analysis from a healthcare-payer perspective. Countries were grouped into influenza transmission zones, with exemplar nations (e.g., UK, China, Ghana) used to infer regional epidemic characteristics.
Vaccines were categorized as current seasonal, improved (based on efficacy, breadth, or duration), or universal, aligned with WHO Preferred Product Characteristics. Universal vaccines were defined as offering high vaccine effectiveness and up to 5 years of immunity.
Simulations assumed 50% annual vaccination coverage among children under 18 years, with sensitivity analyses exploring 20% and 70% coverage scenarios. Compared with no vaccination, current seasonal vaccines were estimated to prevent 1.33 billion infections (95% uncertainty range [UR], 1.20–1.48 billion). Improved vaccines with enhanced efficacy or breadth averted 2.64–2.65 billion infections (95% UR, 2.39–2.93 billion). Universal vaccines demonstrated the largest impact, with an estimated 2.96 billion infections (95% UR, 2.70–3.27 billion) and approximately 826,000 annual deaths (95% UR, 641,000–1,050,000) prevented.
Vaccinating children aged 0 to 10 years proved substantially more effective than targeting adults aged 65 years and older—preventing up to 9.5 times more infections and 2.5 times more deaths—and resulted in the lowest number needed to vaccinate (NNV) to avert one disability-adjusted life year (DALY).
Economic modeling showed that NGIVs would be cost-effective in many high-income countries (HICs) at significantly higher price thresholds than current seasonal vaccines. For example, the median threshold price for universal vaccines reached up to $4,800 per dose in some HICs. In contrast, cost-effectiveness in low-income countries (LICs) would require universal vaccines to be priced below $6 per dose. Improved vaccines often failed to meet cost-effectiveness thresholds in LICs, even at near-zero prices. Sensitivity analyses showed diminishing marginal benefits above 50% coverage and modest additional impact from reduced infectiousness in breakthrough infections.
The findings suggest that next-generation influenza vaccines have the potential to substantially reduce the global influenza burden. However, achieving global equity in access may require tiered pricing models and delivery support for low- and middle-income countries.
The researchers declared no competing interests.
Source: PLOS Medicine
