Transmission of HIV Infection


HIV can transmitted through

Sexual intercourse

The most common way of contracting HIV is through sexual intercourse with a person who has the virus. Condoms do protect against infection but not 100%. HIV can be contracted through vaginal, anal and oral sex. The chance of contracting HIV is higher if that person has a high viral load. A high viral load is more common in people who are not on HIV treatment and are in stage 3 or stage 4 of the disease.

Blood Transfusions

HIV may be acquired from receiving blood which is contaminated with HIV. This is now rare as blood banks routinely test for HIV virus before dispensing the blood.


A hollow needle which is commonly used to draw blood or administer medication is also a possible way of contracting the virus. This can occur by sharing needles with an infected individual or by health-care workers who undergo a needle-prick injury. The chance of contracting HIV from a needle prick injury is about 1 in 300. The chances are increased if the needle was used on a child who is not on treatment because children have a higher viral load. It also depends how much blood was on the needle and how deep the needle penetrated. When this happens it is best to let the blood run freely and to wash the injury under running water. Post-exposure prophylaxis should be sought immediately and the injury should be reported to the person in charge of the facility. Post-exposure prophylaxis is usually taken for 1 month. This decreases the chances of contracting the virus even further.

Contact with contaminated blood

There are other ways in which a person can contract the virus from being in contact with an infected person’s blood. One can either get infected blood into an open wound on the skin or mucous membrane, or have contaminated blood splash in one’s eye. Post-exposure prophylaxis should also be taken in a case like this to decrease chances of contracting the virus.

Mother to Child

HIV infection may be passed from the infected mother to her unborn baby during pregnancy or during the birth process. Chances of infection are less if the mother is on ARVs and the baby is given prophylactic medication after birth.


Breastfeeding is another way through which babies are able to contract HIV. Many mothers in countries in which the HIV prevalence is high are unable to afford formula milk. In cases like these the mothers are told to exclusively breastfeed their baby for the first 6 months of life.