Fig. 2.

Vaccine effectiveness¹against COVID-19 hospitalization in SARI patients who received at least one dose of BNT162b2 XBB.1.5-adapted vaccine using various prior vaccination categories as reference groups.¹Vaccine effectiveness estimates are adjusted for date of symptom onset, age, sex, and number of chronic conditions. ²‘Never vaccinated’ subjects were excluded when calculating the median (IQR) of time since last vaccine dose among patients who did not receive any dose of a COVID-19 vaccine in the 2023–2024 autumn/winter season. ³Stratifications of comparison groups were assessed on matched data per exposure of interest and numbers will therefore not add up to the numbers provided in Table 1. Patient characteristics of these subsets are shown in Supplementary Table S3.