Choosing not to have sex or share needles is the most effective way to avoid possible exposure to HIV, but there are other very effective ways to reduce the chances of transmission and increase your chances of staying healthy. If you are HIV-positive, one of the best ways to protect your partner(s) is to take care of yourself: recent studies suggest that if HIV-positive people use antiretroviral drugs to reduce their viral load to “undetectable” levels, the risks of transmitting HIV to their sexual or drug using partners decreases significantly.

To prevent transmission through sex:
• Get tested for HIV and know the status of your partner(s). You cannot tell if a person is HIV-positive just by looking at them; the only way to know for sure is to get tested. HIV tests look to see if your body has developed antibodies to the virus. Most people will develop HIV antibodies within three months of exposure: some people will develop them sooner, and a few may take as long as six months. If your test comes back “negative” three months after exposure you can feel pretty confident about your results, but because the length of each person’s “window period” can vary, some test centers may encourage you to retest six months after exposure, just to be sure. It is possible to pass HIV on to another person during this window period, even if you do not yet test “positive.”
• Use latex or polyurethane condoms (or other barriers like female condoms or dental dams) during vaginal, oral, and anal sex.
• Use a water-based or silicone-based lubricant, which minimizes the risk of tearing condoms and delicate skin due to friction during sex—and increases sensation. (Avoid lotions and Vaseline because they can cause condoms to break.)

For transmission to occur…
…the virus needs a direct pathway out of the body of a person who is HIV-positive.
…the virus needs a direct pathway into another person’s body.

HIV lives in high concentrations in certain body fluids:
• blood (including menstrual blood)
• semen (cum)
• vaginal fluids
• breast milk

Healthy skin is an excellent barrier to HIV. The virus can pass into another person’s body through:
• broken skin (small sores, tears, and cuts can act like an open door into a person’s blood stream)
• direct contact with a person’s blood (like when needles are used by more than one person)
• mucous membranes (like those inside the vagina, tip of the penis, anus, rectum, mouth, and eyes)
• from mother to baby before or during childbirth, or through breast milk. This is less common in the US today, as women can receive treatment that dramatically reduces the likelihood of transmission to their baby.

There are lower concentrations of HIV in pre-seminal fluid (pre-cum),
making transmission less likely but still possible.

There is not enough virus to make another person sick in: saliva, sweat, tears, urine, feces

HIV is not transmitted through casual contact.
The virus does not:

• move through the air, like the common cold
• travel through food, like E. Coli
• get transmitted through mosquito bites, like malaria
• bore through healthy skin, like some parasites

You cannot get HIV from:
• shaking hands or hugging a person with HIV/AIDS
• using a public telephone, drinking fountain, restroom, door knob, silverware/dishes, swimming pool, or hot tub after a person with HIV/AIDS
• sharing a drink or a meal with a person with HIV/AIDS
• being coughed or sneezed on by a person with HIV/AIDS
• giving blood
• being bitten by a mosquito

People in the US no longer need to worry about getting HIV from transfusions of infected blood or blood products. Most infections in medical settings result from accidental “needle sticks” with a needle that has already been used on a patient with HIV, and primarily involve health care professionals.

To protect themselves and their patients, providers should always use universal precautions:
• Wear latex gloves when coming into contact with blood, breaks in the skin, and mucous membranes.
• Only use needles and gloves once, then discard.
• Wash hands often, including after discarding medical waste.
• Dispose of materials exposed to blood (like needles) properly.

To prevent transmission through needle use:
• Do not share your needles or “works” with other people, whether you are using needles to inject drugs, hormones, or medications like insulin.While HIV generally does not survive for long outside of the human body, it can survive for weeks inside a syringe.
• If you absolutely must share needles or works, be sure to clean them very thoroughly (water, then bleach, then water again) to avoid transmitting HIV and other blood-borne infections like hepatitis.
• Many communities now offer free needle-exchange programs; in some states, you can buy new needles from a pharmacy without a prescription.

For more on the topics addressed above, talk to your doctor.