This web-enabled system has been developed to collect data on any patient hospitalised with laboratory confirmed pandemic influenza A (H1N1). This includes patients diagnosed before admission to hospital and those testing positive during admission. A patient with a positive tests for influenza A or influenza A (H1N1) if not specific for the pandemic strain should be included. Statutory support for disclosure of these data by the NHS, and their processing by the Health Protection Agency, is provided under the provisions of The Health Service (Control of Patient Information) Regulations 2002.

The data are held on an HPA server at a secure HPA site. The server is connected to the secure NHS intranet (formerly known as the "NHSnet") via an N3 connection which provides a high level of security for the data. There is a secure socket layer on the server which means that data flowing between the server and the client are encrypted (128 bit encryption). Access to the system is by username and password. There are several categories of logon, which restrict access to the data dependent on levels of permission agreed, in line with Caldecott principles. This, for example, prevents one trust viewing another's data.