When it comes to sex, undetectable = untransmittable

When you maintain an undetectable viral load, you cannot pass HIV to the people you have sex with. This is true no matter what kinds of sex you are having, and no matter your gender or sexual orientation. It is also true whether or not a condom is used.

You may have heard the phrase undetectable = untransmittable (U=U for short). This phrase was created to get the word out about the benefits of treatment for preventing HIV during sex.

To prevent passing HIV sexually, it is recommended that you wait until you’ve had at least two undetectable viral load results in a row over a six-month period before depending on this strategy.

Studies have shown that a person cannot pass HIV through sex if their viral load is below 200 copies per millilitre. However, it is best for your health if your viral load is below 50 copies per millilitre (that is, your viral load is undetectable by the tests most commonly used in Canada). 

Some people see occasional blips in their viral load. A blip is when your viral load becomes detectable at a very low level on one test and then becomes undetectable again on the next test. A single blip is no reason to panic. It does not mean that your treatment has stopped working or that you can pass HIV through sex. If you have two detectable results in a row, you and your healthcare provider should talk about your options.

Preventing sexually transmitted infections

Having an undetectable viral load does not prevent other STIs (sexually transmitted infections), such as syphilis, chlamydia, herpes and gonorrhea. Condoms can reduce the risk of many STIs, so you might want to use condoms to help prevent STIs.

If I have an undetectable viral load, do I still need to tell someone I have sex with that I have HIV?

Even though there is no chance of passing HIV through sex if you have an undetectable viral load, you may still be legally required to tell your sex partner(s) that you have HIV. At the time this booklet was published there were different rules in different regions of Canada. HIV activists are working to get laws across Canada changed to reflect the science. For the most up-to-date information on when people living with HIV have a legal duty to disclose their HIV status, contact the HIV Legal Network (www.hivlegalnetwork.ca).

What if I have a detectable viral load?

If you consistently take your HIV meds and you continue to have a detectable viral load, work with your healthcare provider to find a combination of HIV meds that might work better for you.

If you continue to have a detectable viral load, rest assured that there are many ways to prevent passing HIV.