What Does an Undetectable Viral Load Mean for HIV?


What Does an Undetectable Viral Load Mean for HIV?

Viral load is the amount of the human immunodeficiency virus (HIV) in someone’s system. If someone’s HIV status is undetectable, it means their viral load is so low that most tests can’t measure it. Someone who is undetectable is extremely unlikely to pass the virus to anyone else.

The treatment for HIV is antiretroviral therapy (ART). It can take 3-6 months of being on ART to become undetectable. Most people who are being treated for HIV have an undetectable viral load. This means it’s very hard for them to pass on HIV. Most times that 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.

A person on ART has to keep taking their medication for their viral load to stay undetectable. If a person stops taking their medication or misses doses, they can become detectable again. Other things like drug resistance, illness and vaccines can temporarily affect a person’s viral load. This is why regular visits to the doctor and testing are part of HIV care plans.

Can someone who’s undetectable still pass on HIV?

In 2016, the PARTNER study followed 1166 serodiscordant couples. This is a couple where one partner is HIV-positive and the other is negative. In each couple, 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. None of them used pre-exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP). These are medications that lower people’s risk of getting HIV. In total, the couples had penetrative vaginal or anal sex about 58,000 times. During the study, there were no cases of the undetectable person giving their partner HIV.

Recently, the PARTNER 2 study was published. The study was very similar to the first one. Except, it lasted eight years and only followed gay male couples.In total, the couples had sex 77,000 times without condoms. There were no cases of the undetectable person giving their partner HIV.

The PARTNER studies show that it might be almost impossible to pass HIV when the positive partner’s viral load is very low. If the partners use condoms or PrEP, that would reduce the chances even more.

Undetectable = Untransmissable or U = U

You may have heard the slogan “U=U”. It stands for “Undetectable = Untransmissable”. It is the slogan for the Prevention Access Campaign. The campaign was to promote the fact that someone who’s undetectable has almost no chance of passing HIV to someone else.

How are undetectable people treated under the law?

Not disclosing your HIV-positive status to a sexual partner is illegal 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 defined a “realistic possibility”. But only 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 have to disclose that they’re HIV-positive. In all other situations of vaginal sex, they have to disclose it. Because the court considers there to be a “realistic possibility” even if their viral load is undetectable.

When it comes to oral or anal sex, there are no definite rulings yet. The Supreme Court has not defined what counts as a “realistic possibility” for these acts.

I’m HIV-negative. What do I do if I’m not comfortable having sex with someone who’s undetectable?

It is always your choice whether 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. It also does not make you serophobic. Being serophobic means being afraid or judgmental of people living with HIV.

It might make you feel more comfortable learning about the chance of passing HIV. Especially, if HIV status is the only concern for you. Most of the time, the person passing HIV didn’t know they were positive. It’s usually from someone with a high viral load who is not on ART. For some people, it can help to know that an undetectable person is very unlikely to pass on HIV.

But, many people’s fears around sex don’t have to do with the actual levels 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 can help to have accurate, up-to-date information about HIV and how it passes from one person to another.

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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