18 In the UK, the burden of RVGE in older children and adults is difficult to estimate but admissions for AGE are 2 per 1000 population in 5–14-year-olds and 7 per 1000 in those 15+ years.19 Hence monitoring changes

in AGE incidence in non-vaccinated older children and adults is critical to assess indirect jq1 impact. Ecological rotavirus vaccine effectiveness studies have primarily focused on mortality, hospitalisations and laboratory detections as a measure of burden.20–27 Severe cases of rotavirus infection will often end up in hospital and receive full diagnostic evaluation. However, many cases of rotavirus infection, particularly in older children and adults, will not attend hospital but will be seen by primary and community healthcare providers. Therefore, in order to better understand the burden of RVGE and AGE on all ages and the impact of routine immunisation on the health system, it is crucial to

examine routine data sources for all health service providers in a defined study area. Taking advantage of a range of regional healthcare facilities in Merseyside, UK, we describe a protocol for an ecological study which will use a ‘before and after’ approach allowing comprehensive evaluation of the direct and indirect vaccine impact following the introduction of the monovalent rotavirus vaccine into the UK’s routine childhood immunisation programme. We will investigate the relationship between socioeconomic deprivation, and vaccine uptake and disease burden. These data will provide evidence to support future rotavirus vaccination in the UK and will inform rotavirus immunisation

policy in other Western European countries.6 Methods Study aim Routine data sources will be used to estimate the direct and indirect effects of monovalent rotavirus vaccination on gastroenteritis indicators in the population of Merseyside, UK, and their relationship to vaccine coverage and sociodemographic indicators. We also hope to identify the key areas that require extended and improved data collection tools to maximise the usefulness of this surveillance approach. The main outcome measures are: Laboratory detections of rotavirus in faecal samples; Admissions to hospital for RVGE or AGE; Attendances to EDs for AGE; Number of nosocomially acquired cases of RVGE; GP and community consultations for diarrhoea and AGE in children less than 5 and in all Batimastat ages; Routine rotavirus vaccine coverage mapping by small area geography; Relative contribution of direct (those vaccinated) and indirect (not vaccinated) effects to overall vaccine benefit in health system usage for both RVGE and AGE; Relationship between socioeconomic deprivation, vaccine uptake and RVGE/AGE incidence. Study setting and location The study will be conducted in the large metropolitan area of Merseyside in North West England which contains the city of Liverpool. Merseyside has a population of nearly 1.