What is AIDS?

AIDS stands for Acquired Immune Deficiency Syndrome.

If HIV isn't treated, the gradual weakening of the immune system leaves the body vulnerable to serious illnesses it would normally be able to fight off. If you develop certain AIDS-defining illnesses or opportunistic infections, you are diagnosed as having AIDS - sometimes also called 'late-stage HIV'.
You cannot catch AIDS and there is no AIDS test. AIDS is not considered a disease, but a syndrome - a collection of different signs and symptoms, all caused by the same virus, HIV.
If you've developed an AIDS-defining illness, this doesn't mean you're on a one-way path to illness and death. Thanks to HIV treatment, many people who were diagnosed as having AIDS in the past are now living long and healthy lives.