Human Immunodeficiency Virus (HIV) occurs when the virus invades cells in the immune system and uses them to make more HIV cells. HIV is a retrovirus, meaning it needs host cells to replicate. The US Centers for Disease Control and Prevention (CDC) reported the first few cases of HIV in 1981. From the late 1970’s to the mid-1980’s, about half of all people with haemophilia became infected with HIV after using contaminated blood products. Many people with haemophilia in Ireland did not know that they had been infected until years later. These sections give information on living with HIV and the excellent treatments that are now available to people with haemophilia.