Wearing condoms is one of the most effective ways to reduce the risk of HIV transmission during anal sex. Of course not everybody uses condoms every time they have sex. Some people may not know their own HIV status and not everybody always knows the HIV status of the person they have sex with. If you have sex without wearing condoms it's important to know about other ways you can manage the chance of getting HIV.

The different ways HIV can be transmitted from person to person can be complex, especially as HIV is not always transmitted every time someone is exposed to it. One important way to manage the risk of HIV transmission is knowing the HIV status and viral load status of you and the other person before having sex. Viral load is the term used to describe how much HIV virus is present in someone’s blood. The terms detectable and undetectable are often used to describe a person’s HIV viral load. 

If a persons viral load is described as undetectable it means the level of HIV virus in that persons blood is so low as to be undetectable in blood tests. Meaning they cannot pass on HIV through sex. If a persons viral load is described as detectable this means the level of HIV virus is high enough to be detected in a blood test and there is a risk of HIV transmission.

It’s still important to understand the ways you can manage any possible risk of HIV transmission. You can find out more in our safer sex section

Treatment as Prevention

The term treatment as prevention or "TasP" describes when a person living with HIV, who is taking anitretroviral medication, has an undetectable viral load. The main purpose of anti retroviral medication is to treat and maintain the good health of the person living with HIV. The secondary benefit of this treatment is lowering the amount of HIV virus in a persons blood to a level so low it becomes undetectable, meaning they cannot pass on HIV through sex. This is known as Undetectable=Untransmittable.

The Partner Study looking at serodiscordant couples (where one person is HIV+ and the other HIV-) examined the risk of HIV transmission when the HIV+ partner had an undetectable viral load and found that there were no HIV transmissions. You can read more about the Partner Study here. Someone living with HIV and adhering to their antiretroviral medication is highly likely to have an undetectable viral load and therefore cannot pass on HIV through sex.

If you would like more information about HIV viral load and HIV have a look at our interactive viral load & safer sex page. Here you can answer questions about the type of sex you have and get specific answers to your questions.