Fact Sheet: Undetectable Viral Load

Key terms and concepts to help you understand what “undetectable” means.

The term “undetectable viral load” pops up everywhere from lab reports and medical journals to social media, dating apps and global awareness campaigns. Here are some key terms and concepts to help you understand what “undetectable” means.

Key Terms

HIV. HIV is the virus that causes AIDS. HIV hijacks cells in your immune system (your body’s defense system) and uses them to replicate (make more copies of itself), destroying those cells in the process.

Image of man receiving hiv test in doctor's officeViral load refers to how many copies of HIV are present in a milliliter sample of blood. Viral load tests show how much HIV is in a sample of blood. These tests are used to check how well HIV medications are working.

Antiretroviral therapy (ART). ART involves taking HIV medications to keep HIV from replicating, or making copies of itself. ART reduces the amount of virus (or viral load) in a person’s blood and other body fluids. The goal of ART is to reduce the presence of virus in your body to undetectable levels.

Undetectable viral load. When copies of HIV cannot be detected by standard viral load tests, an HIV-positive person is said to have an “undetectable viral load.” For most tests used clinically today, this means fewer than 50 copies of HIV per milliliter of blood (<50 copies/mL). Reaching an undetectable viral load is a key goal of ART.

PrEP. Short for “pre-exposure prophylaxis,” PrEP is an HIV-prevention strategy in which HIV-negative people take an oral pill once a day to reduce the possibility of HIV infection.

Being Undetectable: Good News

You can live a healthier and longer life. If you have an undetectable viral load, it means that there is less HIV in your body. Being undetectable means that the virus is less able to attack your immune system cells, which means that there will be less damage to your immune system. This allows people to stay healthier and and live longer.

Undetectable = Untransmittable. People who are undetectable do not transmit HIV to other people through sex. That is the meaning of “undetectable = untransmittable” or “U=U”, a message started by Prevention Access Campaign about what it means to be undetectable. If you have been taking HIV medications for at least six months, have a consistently suppressed viral load (less than 200 copies/mL), and continue taking your HIV medications as directed, you will not transmit HIV to others.

group of u=u supporters
U=U campaign supporters

Treatment as Prevention (TasP). Treatment as prevention refers to taking HIV medications to prevent the sexual transmission of HIV. As with U=U, people living with HIV who maintain undetectable viral loads do not transmit HIV to other people.

Additional information

“Undetectable” does not mean “cured.” An undetectable viral load means that so few copies of the virus are present in the blood that today’s monitoring tests are unable to detect them. Even with an undetectable viral load, however, an HIV-positive person still is HIV-positive. That is why it is important for people living with HIV to continue to take their HIV medications even when they are undetectable.

You will still test positive for HIV if you are undetectable. HIV tests usually detect antibodies, which are part of your immune system’s response to HIV. People living with HIV who are undetectable still have antibodies to HIV which means you will test positive for HIV even if you have an undetectable viral load. If you want to find out if you are undetectable, talk to your HIV care provider who can provide you with a viral load test.

U=U is empowering. The undetectable equals untransmittable message empowers people living with HIV to care for their health by getting to and remaining undetectable, and reduces HIV stigma by challenging the assumption that people living with HIV pose a “risk” to others.

Treatment as prevention is just one strategy for preventing new HIV infections. Other essential tools for HIV prevention include condoms and lube, syringes for people who inject drugs or hormones, PrEP for people who are HIV-negative, regular HIV testing, self-education about HIV and sexual health and open communication with sex partners.

About the author

Emily Land, MA

Emily Land, MA is a writer and the Vice President of Public Affairs at San Francisco AIDS Foundation.