Undetectable Viral Load

People living with HIV who are on anti-retroviral treatment and maintain an undetectable viral load for at least six months do not sexually transmit HIV.

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When someone first becomes HIV positive, the virus replicates quickly in their body. During this stage, their viral load is high, and it is very easy for the virus to be transmitted to sexual partners, especially through unprotected anal sex. Many new HIV infections in New Zealand happen while the HIV positive person is at this stage, and they often haven’t found out yet that they have HIV. As time goes on, their viral load drops and the use of HIV treatment medication can bring their viral load down significantly lower.

New research shows that starting treatment as soon as possible can make it easier for people living with HIV to get an undetectable viral load sooner and live longer and healthier lives.

It is important to note that “undetectable” does not mean cured or free of HIV. It simply means that the treatment has suppressed the virus, therefore, cannot be passed on during condomless sex.


It isn’t as simple as an “undetectable” status on a profile:

Having an undetectable viral load does not provide protection from any other STIs like syphilis, gonorrhoea, LGV or Hepatitis C. STIs are on the rise among gay and bisexual men in New Zealand, including men living with HIV, and can cause serious health problems if untreated.

Sexually Transmitted Infections (STIs) can increase the possibility of HIV transmission in some circumstances. However, the presence of an STI does not increase the possibility of transmission if the HIV-positive person is on effective antiretroviral therapy.

For some people, it could take a while to to get their viral load to an undetectable level, and some people might not ever be able to get there despite adhering to medications. It’s important that HIV positive people are not pressured or expected to have an undetectable viral load.

New Zealand law requires people living with HIV to take “reasonable precautions” to avoid transmission if they do not disclose their HIV status. “Reasonable precautions” has been interpreted by the courts to mean using condoms for sexual intercourse. At present, there has not been a case that has tested whether the courts will interpret having an undetectable viral load as taking reasonable precautions.

When considering the role of undetectable viral load in preventing HIV, there are other things to think about, in particular: whether the HIV positive person been consistent in taking medication; when their last viral load test was and if it is still valid; as well as legal responsibilities. 

Using condoms and lube for anal and vaginal sex is the most effective barrier to sexual transmission of HIV and most other STIs.

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Further Information