Chances of Getting HIV

The Statistics Behind Acquiring HIV

Man unwrapping condom
Man unwrapping condom. Getty Images/Science Photo Library - IAN HOOTON/Brand X Pictures

Many people question their chances of getting HIV if they engage in certain risky behaviors, like unprotected sex or sharing needles during injection drug use

Let's address the probability of a person getting HIV from certain exposures, based on data from the Centers for Disease Control and Prevention, or CDC.

Sexual Contact

According to the CDC, the chance of getting HIV from having sex with a person infected with HIV depends on the type of sex:

  • Receptive anal sex: Risk is 138 per 10,000 exposures or 1.38 percent
  • Insertive anal sex: Risk is 11 per 10,000 exposures or 0.11 percent
  • Receptive vaginal sex: Risk is 8 per 10,000 exposures or 0.08 percent
  • Insertive vaginal sex: Risk is 4 per 10,000 exposures or 0.04 percent
  • Oral sex: Risk is "low" and unable to be quantified

It's important to note that there are a number of variables that influence a person's chance of getting HIV from a sexual encounter with another person infected with HIV. For instance, according to the CDC, using both antiretroviral therapy and condoms decreases a person's risk of getting HIV after a sexual exposure by 99.2 percent. 

In addition, circumcision and pre-exposure prophylaxis, or PrEP, may decrease a person's risk of contracting HIV. 

On the other hand, a high amount of virus in the HIV-infected person's bloodstream may increase the likelihood that their partner will get infected.

In addition, having other sexually transmitted infections increases a person's risk of transmitting HIV. 

Injection Drug Use

The sharing of HIV-contaminated needles or other drug equipment can spread HIV to a non-infected person. According to the CDC, the risk of transmitting HIV by sharing needles is 63 per 10,000 exposures or 0.63 percent.



According to the CDC, the risk of getting HIV from a needle-stick contaminated with HIV-infected blood is 0.23 percent. 

Blood Transfusion

Being exposed to HIV-infected blood during a blood transfusion carries the highest risk of getting HIV — at 92.5 percent. This is rare now due to blood screening techniques. 

Breastfeeding and Mother-to-Child Transmission

Mother-to-child transmission during pregnancy, delivery, or breastfeeding is the most common way that children get HIV.

Women with HIV should not breastfeed, according to the American Academy of Pediatrics -- an exception may be women in developing countries where the benefits of human milk and nutrition outweigh the risk of spreading HIV.

The good news is that mothers with HIV who take antiretroviral medications during pregnancy and have undetectable levels of the virus in their bloodstream can decrease the chance of spreading HIV to their babies to less than 1 percent, according to the CDC. This is assuming that the mothers also avoid breastfeeding their babies after delivery.

Other Exposures

According to the CDC, other exposures to HIV-infected blood through biting, spitting, or sharing sex toys are unlikely to spread HIV, but theoretically can. 

 Good Reads on preventing HIV transmission Include:


Final Thought

Numbers and percentages really are just guidelines. Infection can and does occur after one unprotected sexual encounter or after sharing a needle once. The only way to know if you've been infected is to get tested. Percentages and numbers should not be a substitute for testing and safer sex.


American Academy of Pediatrics. Policy Statement: Breastfeeding and Human Milk. Retrieved September 22nd 2015. Pediatrics 2012 Mar;129(3):e827-41. 

Centers for Disease Control and Prevention. (2015). HIV Among Pregnant Women, Infants, and Children. Retrieved September 29th 2015. 

Centers for Disease Control and Prevention. (2014). HIV Transmission Risk. Retrieved September 29th 2015. 

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