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HIV Transmission

Sexual Transmission

Penetrative Sex:

The primary mode of transmission for HIV in Australia is through sexual transmission; more specifically, vagina or anal penetration. For HIV to be transmitted, the virus must have an exit point from the person who is HIV positive and be able to find an entry point of the person who is HIV negative. HIV is present in seminal fluid and pre-cum, so penetrative sex of the vagina or anus by a penis presents an example of how HIV can be transmitted between one person and another.

It must be pointed out that some people believe that being the insertive partner during sex means that they are not at risk of contracting HIV. This is not correct. HIV exists in vaginal fluids, menstrual blood and anal mucous (or the lining of anus), and therefore HIV can be transmitted onto the insertive partner as well.

With the introduction of biomedical prevention, such as PrEP, there are ways to engage in condomless sex that are safe in terms of preventing the transmission of HIV. However, the most common method of HIV prevention is the use of condoms and water based lube when engaging in penetrative sex.

Oral Sex:

When it comes to oral sex, there are many myths around the transmission of HIV. Now whilst it is biologically possible for HIV to be transmitted through oral sex, it is a physiological improbability. What this means is that it is basically impossible to do so, and even under the most susceptible scenarios no diagnosed cases of HIV being transmitted through oral sex have been recorded. The factors which can increase the possibility however include;

  • If there are cuts and/or abrasions in the receptive partner’s mouth it can inflame the entry point making it more vulnerable to allowing HIV into the blood stream;
  • The insertive partner needs to be HIV positive, have a very high viral load leave and not be on treatment; and
  • Ejaculation needs to occur from the insertive to receptive person.

If you are worried about transmission through oral sex, then there are some tips you can employ to make you feel more at ease, including;

  • Use a condom;
  • Avoid brushing or flossing your teeth before oral sex; and

Rinse or gargle salty water, mouthwash or alcohol to see if you have any cuts in your mouth.

Blood to Blood

HIV can be transmitted through blood to blood contact, such as in the case of sharing injecting or tattooing equipment. It is important to remember that HIV does not live outside of the body for very long, and therefore the blood to blood transmission routes would require HIV positive blood to be directly inserted into the blood stream of someone who is HIV negative – such as through the use of a needle that someone has previously used or with tattooing equipment.

At the start of the epidemic the most common method of blood to blood transmission was through blood transfusions. Since this was discovered several significant steps have been put into the place to reduce and eliminate the possibility of this occurring.

The best way to avoid blood to blood transmission if you are an injecting drug user is to have a new kit for every hit and to use registered tattoo establishments whereby you can see that the equipment has been sterilised. See Safer Injecting.

Parent to Child

When conceiving a child, there is a risk of HIV infection when one parent is HIV positive. However, there are many things that prospective parents can do to reduce the risk. If you or your partner have HIV, then it is best to discuss these options with your HIV specialist before you conceive.

Mother to Child Transmission:

The main method of transmitting HIV from a parent to a child is through mother to child transmission during pregnancy, birth or breastfeeding. However in Australia there are great options mothers can choose to help prevent the onwards transmission of HIV from themselves to their child, including:

  • Being on anti-retroviral treatments (HIV medication);
  • Using anti-retroviral treatments for the child;
  • To not breastfeed as breast milk contains HIV; and
  • Opting for a caesarean section rather than a vaginal delivery as the possibility of something going wrong (i.e., and thus the risk of transmission occurring) is reduced.

Father to Child Transmission:

For HIV positive fathers there are some different steps that can be taken to reduce the risk of transmission of HIV to the child. For example, sperm washing is a treatment option when the father is HIV positive and the mother is HIV negative. Sperm washing concentrates and then separates sperm from the infectious seminal fluid. The sperm can then be safely injected into an egg and implanted in the women’s uterus. This prevents the women from HIV infection and passing it onto the child.

For more information check out this information from the Australian Federation of AIDS Organisations.

However it is again recommended that these discussions take place with an HIV specialist.


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