Enhancing the health and social wellbeing of children and young people living with HIV

Passing on HIV

There are very few ways you can pass on HIV and these are the only ways it is possible to transmit the virus between people. You CANNOT get HIV from kissing, cuddling, or sharing drinks, plates or toilet seats.

To pass on HIV there needs to be a direct way for the virus to get into another person’s blood stream - a bit like going through a door. Getting HIV infected blood on your skin or clothes etc is not a risk. It needs to get into your body (through a cut or tear in the skin). HIV can only survive outside of the body for a very short time - less than a minute - so you can’t pass HIV on through dried blood.

What is U=U?


U= U means:

  • You are taking antiretroviral therapy (HIV meds)
  • You have an “undetectable HIV viral load” – that means your HIV is fully suppressed or “asleep” for more than 6 months
  • You are having regular HIV viral load blood tests and haven’t missed any doses of medicines since your last blood test.

How do we know this?

From a clinical trial called The Partner Study.

This study followed more than a thousand couples, where one of the partners was living with HIV and the other was HIV negative. The partner living with HIV was on antiretroviral therapy and their viral load was suppressed for more than 6 months. The couples lived all over Europe and included both gay and straight couples. The couples were in stable relationships and were already choosing not to use condoms.

Over several years the couples in the study had sex, without using a condom, more than 58,000 times. There were ZERO transmissions of HIV from the partner living with HIV taking treatment, to their HIV negative partner. That proved that if you live with HIV but take your medicines really well you will are not infectious and will not pass HIV onto your sexual partners even if you don’t use a condom or if it splits/falls off. This led to the phrase U=U.

Do I still need to use a condom?

Yes! We advise all teenagers to use condoms because:

  • They prevent unwanted pregnancies
  • They stop you catching other sexually transmitted infections such as chlamydia and gonorrhoea
  • Even if you are using condoms you may want to use an additional method of contraception.

In the Partner Study a few people who were the HIV negative partners at the beginning of the study did catch HIV but when the scientist looked at the HIV virus, it wasn’t the same strand as their regular partners. (Scientist can look at tiny differences in the HIV virus to look at where it came from).  So to catch HIV these people were having unprotected sex with someone else. The person they caught the HIV from can’t have been on effective HIV treatment and may not even have known they were infected.

SO taking your antiretroviral therapy every day:

  • Keeps you healthy
  • Stops HIV being passed onto sexual partners
  • Stops pregnant women passing HIV onto their babies

There is a useful further reading document here that has been created by I-BASE.


HIV can be passed on through:


A really simple way to pass on HIV would be by a blood transfusion, where HIV infected blood is put straight into someone else’s blood stream. In most places in the world now, blood is checked before it is given to other people. In the past lots of people got HIV through blood transfusions but this was before it was known how the virus was passed on.

Semen & vaginal fluids

If an HIV positive person has sex without a condom, HIV can get into the other persons blood because it lives in the semen and vaginal fluid. There does need to be a tear or graze in the other person for the HIV to enter into their body. A condom stops any semen or vaginal fluid getting to the other person, and it also stops unwanted pregnancy and getting other sexually transmitted infections.


If one person has HIV and they inject themselves with a needle, and then another person injects themselves with the same needle directly after, they can pass on HIV. So never share needles.

Breast milk

HIV can be found in breast milk, so if a mother has HIV it is recommended she shouldn’t breastfeed her baby unless it has been advised as safe to do so by a medical professional.