HIV Transmission

Table of Contents

• How HIV Spreads
• Methods of Transmission
• Rare Types of Transmission
• Avoiding Transmission

How HIV Spreads

Many people still do not understand how HIV is passed, or transmitted, from one person to another. Knowing the basics helps you avoid becoming HIV-positive. If you are HIV-positive, these basics help you avoid exposing someone else to HIV.

The spread of HIV can be prevented! There are ways to avoid, or at least reduce, contact with body fluids that transmit HIV. This fact sheet explains how.

HIV is transmitted, or spread, through contact with the following body fluids:

• Blood (including menstrual blood and any blood in saliva, urine, and feces)
• Semen ("cum") and other male sexual fluids ("pre-cum")
• Vaginal fluids
• Breast milk

HIV is also spread through contact with these body fluids; however, usually only health care workers come into contact with these fluids. These fluids are:

• Cerebrospinal fluid around the brain and spinal cord
• Synovial fluid around the joints
• Amniotic fluid around a developing fetus (or baby in the womb)

HIV is not spread through contact with these body fluids:

• Sweat
• Tears
• Saliva (spit)
• Feces (poop)
• Urine (pee)

In other words, you cannot get HIV by touching or hugging someone who is living with HIV, kissing someone living with HIV, drinking or eating from the same cups or utensils as a person living with HIV, or by using a toilet also used by someone living with HIV.

Methods of Transmission

Today, the most common ways HIV is passed from one person to another are:

• Re-using and sharing needles or other equipment for injecting drugs (including steroids or hormones)
• Sex without condoms, other barriers, or treatment as prevention
• Perinatal or mother-to-child (during pregnancy, birth, or breast-feeding)

Re-Using and Sharing Needles for Injecting Drugs

• Injecting Drugs (including steroids or hormones): Many people get HIV when they share the equipment used to inject heroin, methamphetamines, steroids, hormones, or other drugs. Re-using syringes, needles, water, spoons, "cookers," or "cottons" can spread HIV. Be sure to use new syringes and needles only from reliable sources, such as needle exchange programs or pharmacies. Many cities offer free needle and syringe exchange programs. For more information, see our fact sheet on Cleaning Equipment for Injecting Drugs.
• Tattoos or Body Piercings: Tattoos or body piercings should always be done by a licensed professional whose equipment, including ink, is sterile. The U.S. Centers for Disease Control and Prevention (CDC) recommends instruments be used only once and then thrown away. Reusable instruments must be sterilized between uses. Using alcohol to clean instruments is not enough. Proper sterilization involves having instruments steam sterilized, or autoclaved.

Unprotected/Unsafe Sex

Every sexual act (oral, anal, or vaginal) involving sexual fluids has at least some risk. Barriers, such as condoms (male and female), dental dams (thin squares of latex), and latex or nitrile gloves help reduce risk substantially

For people living with HIV, taking HIV drugs can also reduce the risk of HIV transmission to others. HIV drugs can reduce their viral load to undetectable levels. This makes it virtually impossible for their blood, vaginal fluids, breast milk, and semen (cum) to pass HIV on to others. For people who are HIV-negative, taking HIV drugs as pre-exposure prophylaxis (PrEP) can reduce their risk of becoming HIV+ if they are exposed to HIV. For more information on PrEP, please see our fact sheet on PrEP for women.

These methods are part of what is known as HIV treatment as prevention (TasP). TasP does not prevent transmission of other sexually transmitted infections or diseases (STIs or STDs). Please see our fact sheet on TasP for more information.

Unsafe sex (sex without condoms, other barriers, or treatment-as-prevention methods) puts you and/or your partner at risk for HIV or other STIs or STDs. Safer sex (sex using condoms, other barriers, and/or treatment-as-prevention methods consistently and correctly) is the most effective way to protect you and your partner.

Which common sexual activities are most likely to cause HIV transmission when safer sex is not used? Listed from most to least risky:

1. Receptive anal sex ("bottoming"): Taking a penis through one's anus and into one's rectum remains the most risky activity. This is due to the likelihood of small tears in the rectum that allow semen ("cum") to have direct contact with the bloodstream.
2. Receptive vaginal intercourse: This refers to taking a penis into one's vagina. HIV is transmitted from men to women much more easily than from women to men.
3. Insertive anal sex ("topping"): Putting one's penis into someone else's anus and rectum can expose you to HIV.
4. Insertive vaginal intercourse: Putting one's penis into a vagina, especially when the woman is menstruating, can expose you to HIV.
5. Giving oral sex: Using one's mouth to lick, suck, or bite another person's genitals (penis, vagina, or anus) can expose you to HIV. Swallowing semen ("cum"), licking menstrual blood, and having bleeding gums, mouth ulcers, or gum disease will increase your risk of getting HIV.
6. Receiving oral sex: Having your genitals licked, sucked, or bitten is less risky than giving oral sex. However, you can get HIV from your partner, especially if your partner has bleeding gums, mouth ulcers, or gum disease.
7. Sharing sex toys without sterilizing them or using a new condom: This can allow HIV to be transmitted from the first partner to the next one who uses the toy.
8. Mutual masturbation (hand jobs), fingering, and fisting (using a hand to penetrate the anus or vagina): These are extremely low risk, as long as your hand has no open cuts or sores.

Sexual assault or rape can result in transmission if the attacker is living with HIV. The risk increases when rape involves anal penetration, force, and/or multiple attackers. Some forced sexual acts involving wounds can place a victim at very high risk.

Survivors of sexual assault or rape who do not already have HIV should be routinely offered PEP (post-exposure prophylaxis; also called non-occupational PEP, or nPEP) in emergency rooms. This 28-day treatment with HIV drugs greatly reduces the chances of acquiring HIV. PEP is another form of TasP.

PEP must be started within the first 72 hours of exposure to be effective. The earlier treatment is started, the more effective it will be. If PEP is not offered in the emergency room or clinic after a rape or sexual assault, do not be afraid to ask for it.