COVID-19 Infection Survey (CIS): The COVID-19 Infection Survey (CIS) was launched in England in mid-April 2020. Working with the University of Oxford, University of Manchester, UK Health Security Agency, Wellcome Trust, IQVIA and the Lighthouse Laboratories at the UK Biocentre Milton Keynes and Glasgow, it aims to provide information on how many people across the UK have COVID-19 infection at a given point in time, with or without symptoms and how many are ever likely to have been infected. National Immunisation Management Service (NIMS): NIMS is the System of Record for the NHS COVID-19 vaccination programme in England. In early November 2020, NHS Digital took over responsibility from NHSX for the overall management of the technology and data workstream for NHS England's vaccinations programme. The vaccination records included on NIMS are collected from GP practices, community pharmacies and NHS school age immunisation providers. A separate system known as the National Immunisation Vaccination System (NIVS) was established to collect flu vaccine data at the point of vaccination. NIVS will also capture data from the Electronic Staff Record system and match it with vaccination record data on NIMS. Employees details will then be added to NIMS so it is clear the vaccination record relates to a member of staff. This allows the uptake of flu vaccines by staff to be monitored which is important when the health and care system is under pressure because of the COVID-19 pandemic and staff absences due to flu could further impact it. Combined Vaccination File: This is the Combined Vaccination file: ONS derived vaccine data for participants in the COVID-19 Infection Survey (CIS). It contains data on vaccines derived from UKHSA records where available (England), Department of Health and Care Wales(DHCW) vaccine records where available (Wales); or from CIS responses otherwise Data Structure: This dataset is the Combined Vaccination file, which contains the ONS derived vaccination information and a column of CIS IDs. The CIS IDs can be used to link to the CIS attributes extract file, which includes test results from nose and throat swabs and antibody test results, as well as key demographic information by sub-regions. The CIS attributes extract file is also available in SRS, this will also need to be added to analysis projects to enable linkage to the Combined Vaccination file. This linkage is intended to provide a richer source of vaccination information for CIS respondents and enable analysis on vaccine efficacy. No personally identifiable information is included.