Total additional infections, hospitalisations, and deaths averted, and total additional vaccine doses delivered for the Category 2 setting.

We assume AZD1222 is implemented for the first 2 doses, mRNA-1273 for the first booster (dose 3), and a variant-adapted vaccine for subsequent booster doses (doses 4 and 5) with no additional changes to the vaccine product (i.e., no further updating). Impact is expressed relative to the scenario where the primary series plus a booster is delivered to the 10+ years population, with no additional doses. Totals are shown for the period from 1 July 2022 to 31 December 2024. Unless otherwise specified, we assume no additional variant emergence beyond Omicron and its subtypes. The “new variant worse-case scenario” refers to a scenario where a new variant replaces Omicron over 1 month, starting 1 October 2022, with VFR = 10 relative to Delta and severity similar to Delta. Values are the median estimate across 50 model simulations for each scenario. Total modelled events for each scenario are in S1 Table S8, with the total modelled events for the WHO coverage target scenario in S1 Table S10.