The term opportunistic infections refers to a number of illnesses, infections and conditions which occur when the immune system has been damaged by HIV. They are called ‘opportunistic’ because the things that cause them (e.g. viruses, bacteria) are often present in the body and the environment but they don’t cause serious illness in a person with an intact immune system. When the immune system is significantly damaged (for example, by HIV) these common bugs may use the ‘opportunity’ to cause disease. Opportunistic infections can be serious, causing debilitating illness or death. Generally, the risk of developing an opportunistic infection increases as a person’s CD4 count decreases.
Opportunistic infections were very common in the early days of Australia’s HIV epidemic but the effectiveness of HIV antiretroviral treatments means most opportunistic infections are not common any more. If your HIV doctor thinks you are at risk of opportunistic infections (depending on your CD4 count) they may recommend specific antibiotic treatments that act to prevent them. Opportunistic infections include a number of conditions described elsewhere on this site, including thrush / candida and herpes.