The linked dataset contains COVID-19 Infection Survey (CIS) ID's and linked NHS Test and Trace data. This can be used to link to the main CIS attributes dataset, which includes test results from nose and throat swabs and antibody test results and key demographic information by sub-regions. This linkage is intended to increase the amount of testing information available from people who have responded to the survey at any point. The CIS and Test and trace data are independently linked to the Personal Demographics Service (PDS) using deterministic and probabilistic linking methods. Matching CIS and Test and Trace records are then matched using the associate links between these two linkages. The dataset contained in this release includes these associated records. Please refer to the methodological note for detailed information about the linkage method. The CIS and Test and Trace data undergo several cleaning, deduplication, and processing stages before linkage. Only linked data for England is currently available. This dataset contains Test and Trace variables and a column of CIS IDs to enable linkage to the CIS attribute data.