What Does an Undetectable Viral Load Mean for HIV?


What Does an Undetectable Viral Load Mean for HIV?

Someone’s viral load is the amount of the HIV virus they have in their system. If someone’s HIV status is undetectable, it means their viral load is so low that most tests can’t measure it. If someone is undetectable, it’s very unlikely that they’ll transfer the virus to anyone else.

Most people who are being treated for HIV using ART (antiretroviral therapy) have an undetectable viral load. This means it’s very hard for them pass on HIV. Most times people get HIV, it’s from someone who isn’t on ART, or doesn’t know they have it.

Is an undetectable viral load the same as not having HIV?

HIV is treatable but not curable, so someone living with HIV will always have HIV. If they have an undetectable viral load, the virus is still in their body, in very low amounts. So it doesn’t mean the person doesn’t have HIV anymore.

If you’re on ART, continuing to take your medication will keep your viral load undetectable.

Can someone who’s undetectable still pass on HIV?

Someone who’s undetectable has nearly no chance of passing HIV to someone else.

A recent study, called the PARTNER study, followed 1166 serodiscordant couples (where one partner is HIV-positive and the other is negative). In each, one partner was on HIV treatment and had an undetectable viral load. There were both straight couples and gay male couples, although there were more straight couples. The couples were having sex without condoms, and no one used PEP or PrEP (medications that lower people’s risk for getting HIV). In total, the couples had penetrative vaginal or anal sex about 58,000 times.

For the two years of this study, there were zero cases of the undetectable person giving their partner HIV. The PARTNER study shows that HIV transmission might be nearly impossible when the positive partner’s viral load is below a certain number. However, we can’t say so for sure without more studies, and data over longer periods. This is why non-stigmatizing research about HIV is so important!

Overall, the PARTNER study shows that passing on HIV while undetectable is very unlikely, if not impossible. If the partners use condoms or PrEP (pre-exposure prophylaxis), that would reduce the chance even more.

How are undetectable people treated under the law?

Not disclosing your HIV-positive status to a sexual partner is criminalized in Canada. This means that if there is a “realistic possibility” of the HIV-positive person passing the virus to their sexual partner, they have to say so. If they don’t, the person living with HIV could be charged with a crime, usually aggravated sexual assault. This can happen even if they don’t end up passing on HIV.

The Supreme Court has only defined a “realistic possibility” when it comes to penetrative vaginal sex. If the person with HIV is using condoms and has a low or undetectable viral load, they don’t legally have to disclose that they’re HIV-positive. In all other situations of vaginal sex, there is a “realistic possibility” and they have to disclose, even if their viral load is undetectable.

There are no definite rulings yet from the Supreme Court about what counts as a “realistic possibility” when it comes to oral or anal sex.

I’m HIV-negative. What if I don’t feel comfortable having sex with someone who’s undetectable?

It is always your choice whether or not to have sex with someone. There’s nothing wrong with choosing not to if you’re not comfortable with it. Choosing not to have sex with someone for any reason doesn’t make you a bad person or serophobic (afraid or judgmental of people living with HIV).

If HIV status is the only concern for someone, it can make them feel more comfortable to learn about the chance of transmission. Most cases of transmission are from someone who doesn’t know they’re positive, so they’re not on ART and they have a high viral load. For some people, it can help to know that an undetectable person is very unlikely to pass on HIV.

However, many people’s fears around sex don’t have to do with the actual statistics of risk. But these emotions can still have severe impacts on their sex lives. It’s okay to consider your feelings while deciding to have any kind of sex. It’s also important to have accurate, up-to-date information about HIV and transmission.

See the resources below for more.

More info

Viral Load – AIDS.gov

Defines what a viral load is (for people living with HIV), what a normal viral load means, and what changes in viral loads mean. –

Info-Traitment (for HIV and Hep C)

A list of help lines and support programs for up to date information on HIV and Hepatitis C treatment in Quebec. Contact information is for one of several…


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