You can get or transmit HIV only through specific activities. Most commonly, people get or transmit HIV through sexual behaviors and needle or syringe use.
Only certain body fluids—blood, semen (cum), pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids, and breast milk—from a person who has HIV can transmit HIV. These fluids must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur. Mucous membranes are found inside the rectum, vagina, penis, and mouth.
HIV is spread mainly by:
Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV.
Sharing needles or syringes, rinse water, or other equipment (works) used to prepare drugs for injection with someone who has HIV. HIV can live in a used needle up to 42 days depending on temperature and other factors.
By being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers.
From mother to child during pregnancy, birth, or breastfeeding. Although the risk can be high if a mother is living with HIV and not taking medicine, recommendations to test all pregnant women for HIV and start HIV treatment immediately have lowered the number of babies who are born with HIV.
HIV does not survive long outside the human body (such as on surfaces), and it cannot reproduce outside a human host. It is not spread by:
Yes. Having another sexually transmitted disease (STD) can increase the risk of getting or transmitting HIV.
If you are HIV-negative but have an STD, you are about 3 times as likely to get HIV if you have unprotected sex with someone who has HIV.
There are two ways that having an STD can increase the likelihood of getting HIV.
If the STD causes irritation of the skin (for example, from syphilis, herpes, or human papillomavirus), breaks or sores may make it easier for HIV to enter the body during sexual contact.
Even STDs that cause no breaks or open sores (for example, chlamydia, gonorrhea, trichomoniasis) can increase your risk by causing inflammation that increases the number of cells that can serve as targets for HIV.
If you are HIV-positive and also infected with another STD, you are about 3 times as likely as other HIV-infected people to spread HIV through sexual contact. This appears to happen because there is an increased concentration of HIV in the semen and genital fluids of HIV-positive people who also are infected with another STD.
Yes, as an HIV-positive person’s viral load goes down, the chance of transmitting HIV goes down.
Viral load is the amount of HIV in the blood of someone who is HIV-positive. When the viral load is very low, it is called viral suppression. Undetectable viral load is when the amount of HIV in the blood is so low that it can’t be measured.
In general, the higher someone’s viral load, the more likely that person is to transmit HIV. People who have HIV but are in care, taking HIV medicines, and have a very low or undetectable viral load are much less likely to transmit HIV than people who have HIV and do not have a low viral load. However, a person with HIV can still potentially transmit HIV to a partner even if they have an undetectable viral load, because
Yes. This is called HIV superinfection.
HIV superinfection is when a person with HIV gets infected with another strain of the virus. The new strain of HIV can replace the original strain or remain along with the original strain.
The effects of superinfection differ from person to person. Superinfection may cause some people to get sicker faster because they become infected with a new strain of the virus that is resistant to the medicine (antiretroviral therapy or ART) they’re taking to treat their original infection.
Research suggests that a hard-to-treat superinfection is rare. Taking medicine to treat HIV (ART) may reduce someone’s chance of getting a superinfection.
Case reports of female-to-female transmission of HIV are rare. The well-documented risk of female-to-male transmission shows that vaginal fluids and menstrual blood may contain the virus and that exposure to these fluids through mucous membranes (in the vagina or mouth) could potentially lead to HIV infection.
Although HIV transmission is possible in health care settings, it is extremely rare.
Careful practice of infection control, including universal precautions (using protective practices and personal protective equipment to prevent HIV and other blood-borne infections), protects patients as well as health care providers from possible HIV transmission in medical and dental offices and hospitals.
The risk of getting HIV from receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.
It is important to know that you cannot get HIV from donating blood. Blood collection procedures are highly regulated and safe.
The risk of health care workers being exposed to HIV on the job (occupational exposure) is very low, especially if they use protective practices and personal protective equipment to prevent HIV and other blood-borne infections.
For health care workers on the job, the main risk of HIV transmission is from being stuck with an HIV-contaminated needle or other sharp object. However, even this risk is small. Scientists estimate that the risk of HIV infection from being stuck with a needle used on an HIV-infected person is less than 1%.