Understanding HIV

HIV stands for Human Immunodeficiency Virus.

You can become infected with HIV from anyone who already has the virus, even if they don’t appear to be ill and even if they haven’t yet tested HIV-positive. HIV is present in the blood, vaginal fluid, semen and breast milk of people who are HIV positive. It can only be passed on through contact with these bodily fluids by:

  • having unprotected vaginal or anal sex with someone who is infected
  • sharing a needle (for intravenous drug use) with someone who is infected
  • being born to a mother who is infected, or drinking the breast milk of a mother who is infected.

Getting a transfusion of infected blood used to be a way people contracted HIV, but now blood supplies are screened very carefully and the risk is extremely low.

AIDS stands for Acquired Immunodeficiency Syndrome. A syndrome means a collection of illnesses or symptoms. This means AIDS itself is not a specific illness. In the UK people generally do not refer to someone as having AIDS and you can’t contract AIDS, but you might contract HIV through one of the routes mentioned above.

If HIV develops in the body without medication and the immune system becomes weakened, a person may be given an ‘AIDS defining’ diagnosis. This happens when a person has a particular infection that is linked to their HIV and resulting damage to their immune system, such as pneumonia, or their CD4 cell count has fallen below a certain number. CD4 cell count is how the immune system is measured. A low number reflects the damage done by HIV to the CD4 cells which fight infections.

There is currently no licensed vaccine or cure for HIV, though researchers aim to develop both. Before HIV medication was available, being given an AIDS diagnosis would have been more worrying as it means a severe weakening of the immune system. However, with all the advances in medical science, it is possible for people with HIV to get an ‘AIDS defining’ diagnosis, then go on to become completely healthy again. In the UK, HIV is now seen as a manageable chronic condition. 

Aidsmap is a reliable source of up-to-date information about different aspects of HIV.