Infection with the Human Immunodeficiency Virus (HIV) leads to the condition known AIDS or acquired immunodeficiency disease, according to the Mayo Clinic. However because HIV cannot survive for very long outside the human body, the number of ways that it can be transmitted is restricted to contact with contaminated body fluids. This is because the virus is present in fluids such as blood, semen, vaginal fluids, and saliva.
Unprotected Anal Sex
Avert is a charitable organization based in the United Kingdom that was founded in 1986 with the specific aim of fighting the spread of HIV and AIDS by providing reliable information about the diseases. According to the organization, the chances of acquiring HIV via anal sex are about 70 percent. The anal region is more delicate than the vagina; it is more likely to sustain injuries during intercourse. As such, the virus gains access to the body via injuries, which can occur during unprotected anal intercourse.
Unprotected Vaginal Sex
AIDS.org notes that there is a 62 to 66 percent probability of contracting HIV via unprotected vaginal sex. This is because the virus is usually present in the sexual fluids of infected people. Contamination usually occurs when the virus enters a man via wounds on the penis. Whereas the virus usually invades women via the vaginal walls or uterus.
Intravenous Drug Use
AIDS.org estimates that there is a 30 percent chance of getting HIV via intravenous drug use if syringes are shared. The Centers for Disease Control and Prevention further explains that infected blood very often remains inside the needle of a used syringe. The infect blood can thus contaminate the next person who uses the syringe.
Although this is typically thought to be common among users of illegal drugs, this can just as easily happen between people who use prescription intravenous medication if they share syringes. Sharing syringes and needles is extremely ill advised.
Pregnancy and Delivery
According to AIDS.org, there is a 20 to 30 percent probability of babies getting HIV from their mothers during pregnancy and delivery. Infection usually occurs during delivery. However this can be reduced if the infected mother is receiving antiviral medication.
Avert notes that there is a 14 percent probability of infected mothers contaminating their babies via breastfeeding. However this figure can drop to about 4 percent if the mother is on antiviral medication.
The chances of getting HIV from oral sex is less than 5 percent, according to the University of California, San Francisco. Infection usually occurs when infected sexual fluids enter cuts inside an uninfected person's mouth, or when blood from an open sore in an HIV positive patient’s mouth enters an uninfected person’s system.
The Mayo Clinic warns that contact with infected blood carries a high probability of HIV infection. Nevertheless, Avert points out that advances in disease screening and testing have reduced the likelihood of this happening to less than 5 percent.
Tattooing and Body Piercing
Most reputable tattoo and piercing parlors use disposable piercing equipment. Therefore the chances of getting HIV via this method is relatively low according to most sources. In fact, Avert estimates that the likelihood of infection is fewer than 4 percent. So unless the parlor in question reuses piercing equipment, it is reasonable to assume this activity is relatively safe.
Accidental Needle Pricks
The Centers for Disease Control and Prevention acknowledge a concern of acquiring HIV via accidental needle pricks, such as in a health care setting. The likelihood of this actually occurring is less than 3 percent. This is because most clinics, hospitals and health care institutions follow very strict protocols regarding the safe disposal of contaminated material.
The Centers for Disease Control and Prevention notes that there is a very low likelihood of getting HIV via contact sports. The risk of infection occurs only if athletes sustain wounds that are not immediately treated. This provides an opportunity for blood transfer between infected and non-infected athletes.