Impact of vaccination in future scenarios where an additional variant of concern emerges from 1 October 2023.

We assume a variant-adapted vaccine is implemented from dose 4 with no additional changes to the vaccine product (i.e., no further updating). Three variant scenarios are shown: increased severity, where the risk of hospitalisations and severe disease reverts to that of Delta (yellow); additional immune escape, where the VFR increases to 10 (red); and increased severity and immune escape, which assumes both Delta severity and a VFR of 10 (blue). This is compared to the scenario with no new variant (green). (A) Daily hospitalisations and (B) daily infections per million population for the HIC setting with substantial prior transmission and high vaccine access (“Category 1”). (C) Total events (deaths, hospitalisations, and infections) per million population for each variant scenario for the “Category 1” setting, between 1 July 2022 and end-2024. (D) Daily hospitalisations and (E) daily infections per million population for the LMIC setting with substantial prior transmission and low vaccine access (“Category 2”). (F) Total events (deaths, hospitalisations, and infections) per million population for each variant scenario for the “Category 2” setting, between 1 July 2022 and end-2024. Results for the Category 3 setting are in Fig K in S1 Text. Values are reported in Table O in S1 Text. HIC, high-income country; LMIC, lower-middle-income country; VFR, variant fold reduction.