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HIV transmission fact sheet

Do you know how HIV is passed on? 

Check out the myths and facts of HIV transmission.

Key information

HIV is a virus. It cannot live for long outside of the body. HIV can directly enter the body via the bloodstream, or mucous membranes such as:

  • vagina - via the lining of the vagina, cervix or womb
  • penis -  via the urethra or inside of foreskin
  • anus - via the lining which is very delicate.

HIV enters and attacks the cells of the immune system itself - the very thing that would normally kill off a virus. Once HIV is present in the body of an infected person, it is found in their:

  • semen (cum) or pre-seminal fluid (pre-cum)
  • vaginal fluid
  • breast milk
  • blood (including menstrual blood)
  • rectal secretions/mucosa.

There are four main routes of HIV transmission:

  • unprotected vaginal or anal or oral sex (oral sex carries a very small risk)
  • sharing unsterilised injecting drug equipment
  • from mother-to-baby in pregnancy, childbirth or breastfeeding
  • infected blood transfusions, transplants or medical procedures, although most countries have processes in place to prevent this.

Who is at risk?

Anybody is at risk of HIV if infected fluids from an HIV-positive person enters their body. HIV does not exclusively affect certain groups of people. If people living with HIV are on antiretroviral treatment and have an undetectable viral load, the risk of HIV transmission is greatly reduced.


HIV cannot be transmitted by:

  • Surfaces - HIV cannot be transmitted by contact with toilet seats, eating utensils, musical instruments, hugs or handshakes.
  • Air – Breathing the same air as someone living with HIV does not transmit HIV. Coughing, sneezing or spitting cannot transmit HIV either.
  • Kissing - Saliva contains very small amounts of HIV and so the risk is negligible unless both partners have large open sores in their mouth or bleeding gums.
  • Insect bites - Insects such as mosquitoes don't transmit HIV because they do not inject blood when they bite.
  • Sterile needles - Sterilised or new needles and syringes are safe from HIV transmission. Do not share used needles.
  • Water - HIV cannot survive in water, so you are free from HIV transmission in swimming pools, baths or shower areas.


HIV can be transmitted by:

  • Vaginal sex - HIV can be transmitted from woman to man or vice versa. Open cuts and sores increase the risk.
  • Anal sex - Higher risk than vaginal sex because the lining of the anus is more likely to tear, creating an entry point for HIV.
  • Oral sex - Has a very small risk, but only if there are sores in/around the mouth or on the receiving partner’s genitals.
  • Injecting drugs - Shared unsterilised equipment can carry infected blood. Needles used for tattooing and body piercing can also carry a small risk.
  • Blood transfusions/transplants - All donated blood should be tested for HIV; any untested blood carries a risk of HIV transmission to the patient receiving the blood transfusion.
  • Mother-to-child - Transmission can occur during pregnancy, labour, delivery or breastfeeding if HIV treatment is not taken correctly.1
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Last full review: 
01 March 2016

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Last updated:
16 July 2018
Last full review:
01 March 2016