HIV case in King County resistant to preventative medicine

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A possible rare case of HIV transmission in King County appears to be resistant to a so-called miracle drug that prevents people from getting the virus.

HIV Pre-exposure Prophylaxis, better known as PrEP, is a way for people at a substantial risk of getting HIV -- a virus that attacks the immune system --  to avoid infection by taking a pill every day. Currently, hundreds of thousands of people globally are taking PrEP, including over 6,500 people in King County alone.

Recently in King County, a community medical provider notified the health department of a man with newly diagnosed HIV. The medical provider found the man's virus resistant to both of the medications in the PrEP pill, which has the brand name Truvada.

Read a questions-and-answers section about the case and PrEP below from Dr. Matthew Golden, MD, the Director of Public Health’s STD/HIV program.

What exactly is PrEP? What is Truvada?

Truvada is a pill that people who are HIV negative can take to decrease their risk of acquiring HIV infection. This is called HIV pre-exposure prophylaxis, or PrEP. Truvada contains two medications, tenofovir and emtricitabine, both of which are also used to treat HIV in people who are HIV positive.

How effective is Truvada/PrEP in preventing HIV infection?

PrEP is very effective. If taken consistently, it reduces the risk of acquiring HIV through sex by over 90%, and perhaps by over 95%. It is also more than 70% effective in preventing HIV infections transmitted through sharing injection equipment. So while it is very effective, like many drugs, it is not 100% effective.  As the letter below from John Doe illustrates, this is something that all people on PrEP should understand.

How does a person on PrEP get infected with HIV?

This is a complicated question.  As you mentioned in the introduction, hundreds of thousands of people around the world are currently taking PrEP, including over 6,500 people in King County alone. PrEP failure is very rare, at least in people who consistently take their medication.

  • HIV acquisition while on PrEP can occur in several ways:
  • By having sex or sharing injection equipment with someone who has an HIV infection that is resistant to the medications in PrEP and who is not taking effective treatment to suppress the virus;
  • By taking PrEP inconsistently during times of potential exposure to HIV; In very rare instances, PrEP may just not be effective, meaning an individual who is consistently taking their medication becomes infected with a virus that is not PrEP resistant.

Also, if someone starts on PrEP while acutely infected with HIV they can develop a PrEP-resistant infection.

What are details in the case of the King County resident? 

A man newly diagnosed with HIV likely became HIV infected while taking PrEP. The man reported sex only with other men, and both he and his medical provider indicated that he had consistently taken daily PrEP in the months since his last HIV negative test and prior to testing HIV positive.

The virus he is infected with is resistant to both of the drugs contained in Truvada.  He may have been infected by a multidrug resistant form of HIV, though we don’t know for sure. As I said, this has been reported before.  It’s very rare, but we have identified one prior case in King County of possible PrEP failure in a person with a resistant infection. It’s important for people to be aware that PrEP is not 100% effective.  It’s very effective, but not 100%.

What is Public Health doing about this case? 

Public Health, as well as the infected man himself, have attempted to notify his sex partners, and to date none have tested positive for HIV. However, he did not have information to contact all of his partners, so some of them don’t know about his infection.  It is possible that one of them has a PrEP-resistant infection, and that person may expose others to that infection.  We continue to investigate this new case, and to conduct ongoing work to identify persons with Truvada-resistant HIV infection and ensure that such persons receive effective treatment.

What does this mean for the man who is infected with a resistant form of HIV?

PrEP-resistant infections are still treatable. Although the simplest first-line treatments will not work against this man’s virus, he is being treated with alternative medications, and I think the likelihood is very high that he will become virally suppressed and do well long-term.

What’s the number for the STD clinic?

Find us at 206-744-3590 and on our website. We welcome anyone of any age who is interested in protecting themselves against STDs, or who thinks they may be infected.  Or you can click here for list of medical providers who prescribe PrEP.

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