 Dolutegravir DTG is recommended for both treatment-naïve and treatment-experienced, HIV infected adults and paediatric subjects aged 12 years and older and weighing at least 40 kg. One case of suspected DTG hypersensitivity HSR reaction from among over 1500 subjects exposed to the drug at the time of submission in 4Q2012, has been identified; this subject experienced a diffuse maculopapular rash with fever and elevated liver enzymes. Isolated rash was uncommon in the DTG programme with less than 1 of clinical trial subjects experiencing treatment related rash. The pharmacovigilance strategy for DTG and DTG-containing products is to implement a post-marketing risk management program to further quantify the risk of HSR and compare it to that of other integrase inhibitors, and to possibly determine associated risk factors. In addition, the post-authorization safety study will monitor and compare hepatotoxicity and severe skin rash following initiation of DTG or other integrase inhibitor raltegravir RAL or elvitegravir EGV based antiretroviral regimens ARV. Further to be able to distinguish the above symptoms and reactions caused by DTG or the other integrase inhibitor regimen from that of abacavir ABC, known to cause hypersensitivity reaction, the integrase inhibitor groups will be compared in combinations with and without ABC. This five year-long safety study will be conducted through collaboration with EuroSIDA, a well established prospective observational cohort study of more than 18,200 subjects followed in 107 hospitals in 31 European countries, plus Israel and Argentina. This is a five year-long non-interventional prospective cohort study nested within the EuroSIDA study. The study population will include HIV positive subjects over the age of 16 years from EuroSIDA clinical sites, who are new users of DTG or other integrase inhibitors with and without ABC. Following initiation of DTG with ABC based antiretroviral regimen or DTG without ABC or regimens containing other integrase inhibitors RAL, EGV with or without ABC or any other DTG based ARV regimen as monotherapy or two-drug regimens, the study will aim to a Monitor and compare hypersensitivity reaction, b Monitor and compare hepatotoxicity, and c Monitor and compare severe skin rash among all subjects discontinuing DTG or other integrase inhibitor regimens for any reason. 