The U=U message declares that because the HIV transmission risk is zero, PLHIV with a sustained undetectable viral load do not transmit HIV to their sexual partners.
On top of this, top line results of the PARTNER trial showed zero HIV transmissions in 22,000 occasions of sex between gay male couples where the HIV infected partner had an undetectable viral load.
While having an undetectable viral load means there is no risk of transmitting HIV, it will not protect from acquisition or transmission of other STIs like syphilis or gonorrhoea. Because of this, it's a good idea to keep condoms in the mix with casual partners and to have a regular sexual health check-up.
What does undetectable [U=U] mean?
Undetectable – or undetectable viral load – is when the amount of HIV in a person’s body (their viral load) is no longer able to be detected by a standard viral load test. A person living with HIV (PLHIV) who is diagnosed, on antiretroviral treatment (ART) and who achieves and maintains an undetectable viral load (UVL) for at least 6 months has no risk of sexually transmitting the virus to an HIV-negative partner.
However, the risk of other STIs remains.
What does 'treatment as prevention' mean?
Treatment as prevention (TasP) refers to the use of HIV medication to reduce the risk of HIV transmission at a community level. If everyone living with HIV was diagnosed, started treatment immediately and was able to maintain an undetectable viral load, there would be no sexual transmission of HIV. In this way treatment would become a form of prevention.
How long do I have to be on treatment before my viral load becomes undetectable?
It will be possible for most people diagnosed with HIV to reach an undetectable viral load within 3 to 6 months of starting treatment. However, if someone starts treatment very late and therefore has a low CD4 count, or they don’t take their pills as prescribed, then it will make reaching undetectable more difficult. It is important not to assume that everyone who is living with HIV will be able to reach or sustain an undetectable viral load.
Does having an undetectable viral load mean that HIV absolutely cannot be transmitted?
Based on the findings of new research into HIV transmission – including the PARTNER and Opposites Attract studies – we can now confidently say that if someone is able to obtain and maintain an undetectable viral load for at least 6 months, then there is no risk of passing on HIV through sex.
What if I can’t get to undetectable?
Getting to undetectable might not be possible for everyone who is diagnosed with HIV, even if they take their medication as prescribed. It is important that people living with HIV are not pressured or expected to have an undetectable viral load.
How often should I have my viral load tested?
This is something you should discuss with your doctor. A basic guide to viral load testing is to have it done every 3 to 6 months. If, however, you are relying on being undetectable as your primary means of HIV prevention, you may want to consider testing your viral load more frequently. To find out more about this talk to your HIV specialist.