Blood to Blood

Home » HIV » Transmission » Blood to Blood


When someone is living with HIV it means that HIV is present in their blood. Depending on the quantity of HIV in the blood (viral load) it may be possible for HIV to be transmitted to someone else.

There are many ways people’s blood can mix and get into and out of each others bodies. The thing to remember here is that HIV cannot get past skin, unless the skin is broken. Skin is an effective barrier against HIV.


Some activities that can cause blood to blood transmission are:

  • Intravenous drug use (IV drug user)
  • Tattooing, piercing and whilst giving or receiving medical treatment including first aid
  • Menstruating women (women on their period)


Intravenous Drug Use

This is only a risk if you are sharing needles or other drug using equipment. As you do not know if someone else is living with HIV, you can never know if it is safe to share. If you do share the other persons blood can stay on the equipment or inside the syringe and will be injected directly into you when you take your turn. If the person you are sharing works with is HIV positive then the chance of you contracting HIV from sharing works with them is 90-100%.

Information about where to get clean needles and other drug using equipment can be found on our links page.

Unfortunately when most people decide to inject for the first time, they often don’t have their own works and therefore end up using someone else’s. If you do this you could be at a very high risk from contracting HIV and/or Hepatitis C. If you have shared injecting equipment, even once, with anyone, we recommend you consider getting tested for HIV.


Tattooing, Piercing and Giving or Receiving Medical Treatment (including first aid)

Care needs to be taken when giving and receiving medical treatments, (including first aid) and giving or receiving tattoos or body piercings.

We would recommend the use of universal procedures at all times, but especially in cases where one person is dealing with another persons blood or body fluids.


Menstruating Women (women on their period)

Sharing sexual activity with women, who are living with HIV and on their periods (menstruating), carries a higher risk of HIV transmission than with sexual activity at other times of the month. This is because the HIV is present in her vaginal fluid and the blood from her womb.

For more information about preventing blood to blood transmission please check our Prevention section.

If you are concerned you may have been at risk form blood to blood transmission there may be some things you can do to reduce your chances of developing HIV. Please check out our PEP page or call our confidential helpline on 061 316661.