The most common route for HIV infection is via sexual contact with an infected partner, particularly among men who have sex with men (MSM), but the virus can also be spread by sharing drug injecting equipment, vertical transmission during childbirth or from breast milk, occupational exposure to infected blood/body fluids e.g. needlestick injury from an infected patient, or from blood and blood products transfusion (though uncommon in developed countries due to screening processes).
Due to advances in medical treatment with antiretroviral drugs, people with HIV can have a near normal life span and may never develop AIDS. There is no vaccine for HIV infection however there is post exposure prophylaxis (PEP) available for those who have come into contact with, infected bodily fluids, which significantly reduces the risk of contracting the virus. Pre-exposure prophylaxis for those at risk may also reduce the risk of infection. In Northern Ireland, PrEP is available to people who are considered to be at higher risk of contracting HIV.