HIV is transmitted from one person to another via body fluids, which carry enough HIV to cause infection.
When it comes to HIV there are many different ways the virus may be acquired. The 4 main ways that HIV can be acquired are via breastfeeding, blood-to-blood contact, anal sex as well as vaginal sex. Being aware of the routes of transmission of HIV can significantly lower a person's chances of contracting the virus.
Exposure to HIV does not always lead to infection. The ease or difficulty of transmission depends on a number of different cofactors. In order to contract the virus, a person must be exposed to a certain viral load before becoming infected. A person may be able to have sex with an infected individual several times and not become infected. It is also possible for a person to have sex just once and become infected from that single contact.
The most efficient way of HIV transmission is blood-to-blood contact. When sufficient amounts of HIV-infected blood get into the body, infection may occur. HIV cannot be transmitted via blood to skin contact, the infected blood must have a means of entry into the bloodstream through a cut, open wound, or directly injected into a muscle or vein.