What is HIV?

HIV stands for human immunodeficiency virus. HIV is a virus which attacks the body’s immune system, specifically the CD4 cells (otherwise known as T cells) which are there to help the immune system to fight off infections.

If left untreated, HIV will reduce the number of CD4 cells in the body, making a person more susceptible to infections. If left untreated, HIV can eventually destroy so many of these infection-fighting cells that the body becomes unable to fight off infections and disease. This leads to a syndrome known as AIDS, or acquired immunodeficiency syndrome.

How do you get HIV?

HIV is found in the bodily fluids of someone who is HIV positive, which includes blood, semen, vaginal and anal fluids, and breast milk. The most common way of getting HIV in the UK is by anal or vaginal sex without a condom. Other ways of getting HIV include:

  • using a contaminated needle or injecting equipment.
  • transmission from mother to baby during pregnancy, birth or breastfeeding.

HIV is a fragile virus and does not survive outside the body for long. It cannot be transmitted through sweat or urine. Read more about how you get HIV.

Getting tested for HIV

If you think you might have been exposed to HIV, seek medical attention as soon as possible. The only way to find out if you have HIV is to have an HIV test. This involves testing a sample of your blood or saliva for signs of the infection. Find out more about getting a HIV test.

How common is HIV?

Overall, the number of people living with HIV in the UK continues to rise and the number living with undiagnosed HIV remains high.

According to Public Health England, at the end of 2014 there were an estimated 103,700 people in the UK living with HIV. The majority became HIV positive through sex (45,000 gay and bisexual men and 54,100 heterosexuals).

An estimated 18,100 people with HIV (17%) do not know they have HIV.
Around one in every 620 people in the UK has HIV, but the two groups with highest rates of HIV are gay and bisexual men (approximately 1 in 20) and Black African heterosexuals (approximately 1 in 56 men and 1 in 22 women).

The World Health Organization estimates that around 37 million people in the world are living with HIV. The virus is more common in many sub-Saharan African countries.

What is AIDS?

AIDS stands for acquired immune deficiency syndrome. It means a collection of illnesses caused by a virus that causes damage to an individual’s immune system, making it weak. Only an HIV positive person can be diagnosed with AIDS. Doctors in the UK are less likely to use the term AIDS nowadays, and instead will talk about late stage advanced HIV disease.