How is HIV transmitted?

HIV is relatively difficult to transmit. Infection is only possible if sufficient quantities of the virus enter one body from another. This usually happens through unprotected sex or drug consumption if paraphernalia is shared. There are effective ways to protect against an HIV infection.

When is there a risk of HIV?

The risk of transmitting HIV varies depending on the situation and the sexual act. Unprotected sex does not necessarily result in infection, but having unprotected sex just once can be enough for transmission. An HIV risk exists only in cases when bodily fluids containing a sufficient quantity of the virus enter the body:

  • During anl or vaginal sex: HIV enters the body via anal or vaginal mucous membranes if there is no protection with condoms or PrEP
  • During drug consumption: HIV can enter the bloodstream when syringes and needles are shared
  • During pregnancy, childbirth or breastfeeding: via the placenta, through contact with blood or vaginal secretions, or via breast milk if the mother is not taking medications to treat HIV

The risk of transmitting HIV is increased when an especially high amount of the virus is present in the blood and bodily fluids. This is the case, for example, in the two to four weeks after a fresh HIV infection, as this is the time when the virus multiplies most rapidly (primary infection).  This is the stage when most transmission takes place.

HIV therapy suppresses the replication of the virus in the body so effectively that the virus eventually becomes undetectable in the blood. At this point, HIV is no longer transmissible.

Not a risk in everyday life

HIV cannot be transmitted through everyday activities. There is no risk of infection from sharing clothes, cooking utensils, cutlery, crockery or public toilets. Hugging, kissing and even oral sex are also safe. Also, semen in the eye or mouth is not sufficient to transmit HIV.

HIV transmission requires an infectious fluid containing a sufficient quantity of the HIV virus and a suitable portal of entry. The anal mucosa is susceptible to the virus entering the body, whereas the oral mucosa is not. Infection is only possible if sufficient quantities of the virus enter the body. Unprotected anal or vaginal sex presents the biggest risk of this.