Seasonal influenza in the UK represents a substantial economic and public health burden. Each year, there are an average of 600 influenza-related deaths and an estimated £1.3 billion cost to the economy due to influenza-associated lost working days. In some years, influenza-related deaths have even been as high as 10,000. Correspondingly, the influenza vaccine is recommended by the National Health Service (NHS) and is made readily available across the UK. The influenza vaccine has historically been shown to be a safe and effective means of reducing influenza associated disease and complications. Despite this fact, influenza vaccine uptake rates have failed to reach optimal levels across all subgroups. Amongst adults aged 65 and over, the UK has consistently been a top-performer in Europe in terms of vaccine uptake, but amongst at-risk individuals under 65 (where at-risk is defined by certain pre-existing co-morbidities, aged 65 and over, pregnancy, living in a long-term care facility, or caring for an elder), these rates has remained well below the WHO's target of 75%. In this study, we aim to assess the association of various patient and practice level factors with seasonal influenza vaccine uptake. The factors of focus for our study encompass areas including patient and practice level demographic characteristics, at-risk health conditions, socioeconomic indicators, living arrangements, pneumococcal vaccine uptake, practice-level vaccine promotion, and practice-level influenza vaccination advice. Identifying significant factors of influenza vaccine uptake may help to better understand these disparate uptake rates that have consistently been observed in the UK.
The UK's seasonal influenza vaccine uptake rate amongst adults 65 and over represents some of the highest in Europe, yet uptake rates amongst at-risk adults below 65 are sub-optimal. These uptake rates have remained relatively stagnant for nearly two decades. To better understand this varied performance, we aim assess the association between various patient and practice with seasonal vaccine uptake. We have designed a 7-year multi-level retrospective cohort study amongst adults aged 18 and over in England. The use of the English data permits the linkage of patient level socioeconomic data to our cohort. After applying our detailed inclusion and exclusion criteria, we have identified ~3.3 million eligible patients, constituting our dynamic reference study cohort from which analytical cohorts will be built. These criteria ensure that patients are followed for an adequate amount of time, to more accurately assess their characteristics and outcomes. Seven seasonal cross-sectional cohorts will be constructed, where patients are observed for one full season. The primary outcome is whether or not a patient receives a seasonal influenza vaccine in a given season. Secondly, a longitudinal cohort will be constructed, consisting of patients continuously followed for 7 years (2010-2017). The primary outcome is whether or not a patient receives an influenza vaccine during within each season. Odds Ratios (ORs) of vaccination will be estimated via General Estimating Equation (GEE) Logistic Regression models, adjusting for clustering at the practice level (cross-sectional analysis) as well as within-patient correlation (longitudinal analysis). All models will adjust for patient and practice level factors encompassing areas including demographic characteristics, at-risk health conditions, socioeconomic indicators, living arrangements, pneumococcal vaccine uptake, practice-level vaccine promotion, and practice-level advising of vaccination. A secondary analysis will assess differences in characteristics between practices in the top and bottom 10% of vaccine uptake rates, when stratified by at-risk categories.
Primary outcome patient receives a seasonal influenza vaccine (per season)
Paul Grootendorst - Chief Investigator - University of Toronto
Matt Loiacono - Corresponding Applicant - Sanofi Pasteur SA (France) - office closed
Ayman Chit - Collaborator - Sanofi Pasteur SA (France) - office closed
Edward Thommes - Collaborator - Sanofi Pasteur SA (France) - office closed
Helene Bricout - Collaborator - Sanofi Pasteur MSD ( closed )
Luke Skinner - Collaborator - Sanofi Pasteur SA (France) - office closed
Matt Loiacono - Collaborator - Sanofi Pasteur SA (France) - office closed
Paul Grootendorst - Collaborator - University of Toronto
Rob van Aalst - Collaborator - Sanofi Pasteur SA (France) - office closed
Salaheddin Mahmud - Collaborator - University of Manitoba
2011 Rural-Urban Classification at LSOA level;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation Domains