Since 1989, children with HIV infection presenting to treatment services and infants born to HIV-infected women in the UK and Ireland have been notified to the National Study of HIV in Pregnancy and Childhood (NSHPC) at the Institute of Child Health through two surveillance schemes. Notifications of HIV-positive pregnancies are made through an active obstetric reporting scheme. Paediatric notifications of all infants born to HIV-infected women as well as those found to have HIV infection after birth are made primarily through the British Paediatric Surveillance Unit (BPSU). NSHPC collect demographic data and limited follow up information on these children.

In 2000, CHIPS was established to gather more detailed follow-up data on the HIV infected children reported to the NSHPC. The NSHPC notifies CHIPS of any children with confirmed HIV infection, and for each of these children a baseline and follow-up CHIPS questionnaire is sent to the respective clinic for completion.

CHIPS initially included 16 UK and Irish clinics enrolling children into PENTA trials (the Paediatric European Network for the Treatment of AIDS). During the first year of CHIPS, baseline information was collected on all children in follow-up at participating clinics since 1 January 1996. However since 2003, follow-up information and selective baseline information has been collected from new clinics joining CHIPS.