Presentation (CTI)

OBJECTIVES: High vaccination coverage is essential for measles control, yet achieving and sustaining near-universal uptake requires substantial public health investment. While epidemiological modelling has shown that herd immunity for measles emerges only at very high coverage levels, less is known about the economic efficiency of increases beyond commonly targeted thresholds. Using a Susceptible-Exposed-Infectious-Recovered (SEIR) model of a historic measles outbreak in an isolated paediatric population, this study estimated the cost per measles case averted at 85%, 90%, 95%, and 99% vaccination coverage to inform resource allocation for measles elimination strategies.
METHODS: A previously validated stochastic SEIR model, parameterised using the Hagelloch measles outbreak dataset, applied vaccine-induced reductions in susceptibility based on measles-mumps-rubella (MMR) vaccine efficacy. Coverage levels of 85%, 90%, 95%, and 99% were simulated using repeated stochastic runs. Health outcomes were measured as measles cases averted relative to a no-vaccination counterfactual. Vaccination costs were estimated using per-dose MMR acquisition and administration costs. Medical costs associated with measles infection were estimated using published UK cost-per-case estimates, adjusted to present-day values. Economic outcomes were expressed as vaccination costs, measles treatment costs, and cost per case averted between successive coverage thresholds.
RESULTS: Increasing vaccination coverage reduced measles transmission. Mean infection rates declined from 24.65% at 85% coverage to 10.89%, 3.51%, and 0.82% at 90%, 95%, and 99%, respectively. Case-treatment costs decreased accordingly, from £211.77 at 85% coverage to £93.53, £30.14, and £7.06 at 90%, 95%, and 99% coverage, respectively. Vaccination costs increased from £53.83 to £62.69 per child. Reductions in transmission were highly non-linear, with infection rates collapsing as coverage approached herd-immunity thresholds.
CONCLUSIONS: Increases in measles vaccination coverage produced disproportionate reductions in infection burden and treatment costs. Economic benefits accelerated as coverage approached elimination thresholds, supporting the idea of investment in interventions that improve uptake beyond conventional targets.