Transmission of HIV
HIV can be transmitted:
Most commonly (High Risk):
- By mucosal exposure to infected bodily fluids, including blood, semen, pre-ejaculate, vaginal fluid and rectal fluid, usually through unprotected sexual activity
- By direct exposure to infected blood, usually through sharing needles with infected individuals
Less commonly (Low Risk):
- From infected mother to baby during pregnancy, childbirth or breastfeeding. The use of HIV medication during pregnancy can effectively reduce the risk of mother-to-baby transmission to less than 1%.
- Accidental needlestick or sharp injuries, mostly among healthcare professionals. The use of post-exposure prophylaxis can reduce the risk of infection.
Unlikely but possible:
- The risk of transmission through oral sex is generally low, but the risk is increased if cuts, ulcers/open sores or gum disease is present
The HIV virus cannot enter intact (unbroken) skin, so, HIV CANNOT be transmitted by:
- Insect bites (e.g. by mosquito or ticks)
- Sweat, tears or saliva that does not contain blood of an infected person
- Sexual activities that do not involve exchange of bodily fluids, e.g. touching
- Social activities such as hugging, shaking hands, closed-mouth kissing, toilets seats, swimming pools, telephones, sharing food or eating utensils
Risk of HIV transmission per exposure from a known HIV-positive individual not on ART.
Source: Cresswell, F., Waters, L., Briggs, E., Fox, J., Harbottle, J., Hawkins, D., ... & Fisher, M. (2016). UK guideline for the use of HIV post-exposure prophylaxis following sexual exposure, 2015. International journal of STD & AIDS, 27(9), 713-738.
HIV can be prevented by using condom correctly and persistently during sex and avoid sharing needles with others. The use of HIV medication by infected mothers during pregnancy can reduce the risk of transmission to their babies. In addition, breastfeeding should be avoided by mothers with HIV to prevent transmission through breastmilk.
Pre-exposure prophylaxis (PrEP) is a method to prevent HIV infection for people who are HIV-negative to take anti-retroviral medication to reduce the risk of infection if later exposed to the virus, e.g. to engage in sexual activity with a person who is HIV-positive. See PrEP.
Post-exposure prophylaxis (PEP) is a treatment consists of 28 days of anti-retroviral medication prescribed by doctor to prevent HIV infection after possible exposure to HIV, e.g. after unprotected sex. See PEP.