Undetectable Viral Load

Evidence shows that an HIV positive person, who is taking HIV medication, resulting in an undetectable viral load, has substantially reduced risk of passing on HIV to sexual partners. This is great news.

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 in 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 HIV-positive people 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 stopped the virus from replicating therefore making it far less likely to be passed on during unprotected sex.

Initial findings from the PARTNER study show that the transmission risk could be as high as 4% if the HIV positive partner on HIV treatment with undetectable viral load is the top, and 1% if he’s the bottom. More results are due from this study in the next year or two.

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. They can cause serious health problems if untreated and can increase the risk of HIV transmission.
  • A person’s viral load can fluctuate and increase the risk of HIV transmission if they have another STI or the flu, and during breaks in taking HIV medications. Maintaining good general health and preventing other STIs can help keep viral load down.
  • For some people, it could take a long time 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: having other STIs or the flu, which can increase viral load; 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 way to prevent sexual transmission of HIV as well as other STIs.

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Further Information