Are there more risks to PrEP we don’t know about?

A man in King County, Washington has been diagnosed HIV after having been on PrEP (Truvada) for months prior to his positive test. An extremely rare case in individuals who take Truvada for prevention, the drug has proven to be resistant to the infection.


PrEP can lower risk of HIV transmission by 90%, if taken properly—although this is skewed with numbers as low as 86% and as high as 99%. Needless to say, like many drugs, it is not 100% effective.

According to Outbreak News Today, Matthew Golden, MD, who is Director of Public Health’s STD/HIV program said the patient likely became HIV infected while taking PrEP.

This is the fourth incident in which patients on PrEP have been diagnosed with HIV.

While it was reported that approximately 136,000 Americans were taking Truvada as of 2017, this number falls short of the CDC’s recommendation for 1.2 million gay and bisexual men (1 out of 4) to be on PrEP.

1 thought on “Are there more risks to PrEP we don’t know about?”

  1. The King County case cannot

    The King County case cannot be considered a confirmed case of PrEP failure, since we have only the patient’s self-report that he was taking the medication as prescribed. In the three documented PrEP failure cases to date, the patient’s adherence was independently confirmed through blood levels of the drug tracked over time. In PrEP trials, subjects frequently exaggerated their adherence in comparison to their measured blood levels


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