Viral load or U = U
When a person is using effective HIV treatment, sexual transmission is not possible. This statement is also expressed as “undetectable = untransmittable” or “U = U.”
Here are a few concepts to help explain this.
The viral load represents the quantity of HIV in the blood of an HIV-positive person. The higher the viral load, the more the risk of transmission increases. The lower the viral load, the more the risk of transmission goes down. Anti-HIV medication reduces the viral load.
A viral load is called undetectable when the quantity of HIV is very low, meaning fewer than 200 copies per millilitre of blood. When the viral load is undetectable and stays that way, after a certain time, HIV cannot be sexually transmitted. As such, it is untransmittable.
A person living with HIV who takes effective HIV treatment and maintains an undetectable viral load does not transmit HIV to their sexual partners.
To confirm an undetectable viral load, three conditions apply:
- HIV medication is taken as prescribed (without forgetting doses).
- The quantity of virus in the blood (viral load) is measured two or three times per year.
- The viral load continues to be undetectable, meaning fewer than 200 copies per millilitre of blood.
Québec health authorities have not documented a single case of sexual transmission of HIV through oral, anal or vaginal sex if these three conditions are met. However, HIV treatment does not protect you against other STBBIs.
Adjusting your sexual practices
Do you want to adjust your safer sex practices based on your viral load or that of your HIV-positive partner(s)? Here are a few elements to talk about together:
- When were your last HIV and STBBI tests?
- Are HIV medications taken as prescribed?
- Has the viral load been measured and confirmed as being undetectable (fewer than 200 copies per millilitre of blood) twice in a row over a period of four to six months?
In all cases, coming to a clear agreement with your partner(s) is the best way to negotiate your practices.
If your viral load is detectable
If you're HIV-negative
You may have seen guys post that they’re “undetectable” on hookup sites or apps. In general, undetectable guys tell people they’re undetectable, say it up front to their partners or confirm it if they’re asked. If you’re uncertain about your partners’ viral load, you can use other highly effective prevention measures, such as condoms or PrEP.
An important element to consider if you're living with HIV
In Canada, a person living with HIV must disclose their status to a sexual partner before having sex, otherwise they can be reported and criminally prosecuted. However, there should be no prosecution if your viral load:
- Is low (fewer than 1,500 copies per ml of blood) and you use a condom when having sex.
- Is lower than 200 copies and laboratory tested every four to six months (meaning two or three times a year).
For more information, visit the criminalization of HIV exposure section on the COCQ-SIDA website (in French only).