Changing socio-demographic determinants of seasonal influenza acceptance in England during the pandemic and a framework for predicting future acceptance

ObjectiveTo assess the current level of seasonal influenza vaccine acceptance in England and establish the evolving socio-demographic determinants of seasonal influenza uptake and intent-to-vaccinate behaviours between 2020 and 2022. To provide a framework for predicting future rates of seasonal influenza uptake at sub-national scales in England. DesignTwo cross-sectional online surveys analysed using a Bayesian time-series multilevel model followed by poststratification to re-weight against English census data. SettingEngland, September 2020 to July 2022. Participants28,748 English adults, 18 years of age and older. Main outcome measuresThree response variables: whether an individual was offered a seasonal influenza vaccine on the NHS in the last 12 months, whether this offer was accepted, and whether they would accept a seasonal influenza vaccine in the next 12 months. ResultsIn the 2021-22 flu season, 56.3% of adults in England were offered the seasonal influenza vaccine, marking a significant increase of 10.7 percentage points compared to the 2019-20 season, due to the expanded rollout of the programme during the pandemic. Acceptance of the seasonal influenza vaccine saw a marked rise during this period across most age groups and particularly among individuals aged 50 and over. However, intentions to accept the vaccine in the next 12 months showed a slight decline across the English adult population between 2020 and 2022 surveys. Socio-demographic traits play a significant role in shaping vaccine behaviours, with age, gender, education, ethnicity, and religion influencing the likelihood of being offered the vaccine, accepting it when offered, and intending to receive future vaccinations. Noteworthy differences were observed across demographic groups, particularly between Black/Black British and White respondents, although gaps in acceptance between socio-demographic groups in the 65-and-over cohort were narrower than for population as a whole. Of particular concern is waning intent-to-accept behaviours among Asian and Asian British groups, as well as Hindus and Punjabi speakers. Regional disparities also emerged, with estimates for flu vaccine receipt and future intent to accept a flu vaccine relatively low in London, especially inner London. Predictions of flu vaccine uptake generated from 2022 data correlated well with the observed UK Health Security Agency-reported uptake in the subsequent 2022-23 flu season, highlighting the ability of multilevel regression and poststratification to accurately capture future intentions. ConclusionsThe findings underscore the significant progress made in increasing seasonal influenza vaccine uptake among adults in England during the 2021-22 flu season. Despite these improvements, disparities persist across socio-demographic groups, spotlighting the need for targeted interventions to address uptake inequity. The slight decline in intention to accept the vaccine in the general adult population warrants attention. Furthermore, regional disparities emphasise the importance of tailoring vaccination strategies to address specific geographical contexts. The strong correlation between predicted and observed vaccine uptake and observed indicates the utility of predictive modelling in informing future vaccination behaviours and public health interventions. Overall, these findings provide valuable insights for policymakers and public health practitioners to enhance influenza vaccination efforts and mitigate the burden of influenza-related illness in England.