BACKGROUND: Seasonal influenza causes around 15,000 deaths yearly in the UK. While vaccination is a useful prevention measure, uptake is low, related to factors such as deprivation, age, sex, and ethnicity. Liverpool is a diverse yet deprived city, with potentially interacting population-level factors which require examination prior to targeted intervention development. METHODS: A retrospective cross-sectional analysis of electronic health records in Liverpool used meta-analysis to examine associations between vaccine uptake and deprivation, sex, age group, and ethnicity. RESULTS: Overall prevalence rates for vaccination between September 2022 and March 2023 were 25·8 % (95 % CI: 23·8 % to 28·0 %). All factors were associated with uptake, which was lowest in: more deprived General Practices (family doctor
primary care physician), males, children aged 0-1, and in people identifying as Any Other ethnicity. Individuals identifying as White or Mixed/Multiple ethnic groups were most likely to be vaccinated, while those identifying as Black, Black British, Caribbean or African, and Asian or Asian British had lower uptake. Similarly, rates were higher in individuals aged 2-3, 4-10, and 65+ than 16-64, while no difference was found between the latter group and ages 11-15. Deprivation did not interact with age, sex, or ethnicity. CONCLUSION: These findings support that deprivation, age, sex, and ethnicity influence influenza vaccine uptake, and that they do so uniquely in Liverpool. While deprivation did not interact with other characteristics, this may be due to the impact of inequality (large deprivation gap between richer and poorer areas) on the whole city, as this is as a social stressor that can impair health outcomes for all, not just those in more deprived areas. Future work should investigate experiences of people in areas with lower uptake in Liverpool, to understand potential barriers and enable targeted intervention.