Optimising the introduction of multiple childhood vaccines in Japan: A model proposing the introduction sequence achieving the highest health gains

•When several new vaccines are available, the sequence of vaccine introduction affects health gains.•A new model is presented that can help decision-makers to optimize vaccine introduction.•For Japan, the model estimates that 500 billion Yen achieve a QALY gain of 72,288.•Without optimization, the same budget would achieve a 20% lower QALY gain. Many countries struggle with the prioritisation of introducing new vaccines because of budget limitations and lack of focus on public health goals. A model has been developed that defines how specific health goals can be optimised through immunisation within vaccination budget constraints. Japan, as a country example, could introduce 4 new pediatric vaccines targeting influenza, rotavirus, pneumococcal disease and mumps with known burden of disease, vaccine efficacies and maximum achievable coverages. Operating under budget constraints, the Portfolio-model for the Management of Vaccines (PMV) identifies the optimal vaccine ranking and combination for achieving the maximum QALY gain over a period of 10 calendar years in children