People living with HIV often have questions about the risk of passing HIV to their negative partners. Good news--recent research has shown that patients who use antiretroviral therapy (ART) to maintain consistently undetectable levels of HIV are effectively unable to transmit HIV to their sexual partners. HIV treatment with ARTs as transmission prevention, commonly referred to as “Undetectable = Untransmittable,” or U=U, is treatment as prevention (TasP) and is gaining traction in preventing new HIV cases.
As U=U has grown in popularity, the term has popped up outside of the exam room. For example, people with undetectable viral loads may include the abbreviations U=U, tasp, or [u+] in their dating profiles, to inform potential partners of their virally suppressed status.
Here are the basics on U=U that providers need to know:
How does U=U prevent HIV transmission?
If a person adheres to their ART regimen and has an undetectable HIV viral load, they have effectively no risk of passing the HIV virus to anyone through sex—oral, anal, or vaginal. To take it back to basics—once someone is infected with HIV, the virus begins multiplying in the body. With HIV treatment, an ART regimen stops the virus from multiplying, and ultimately suppresses the viral load so low that it is “undetectable.” This usually happens within one to six months on consistent ART for most patients.
What’s the evidence for U=U?
Support for U=U comes predominantly from four studies: HPTN 052, PARTNER, PARTNER 2, and Opposites Attract. These studies followed HIV serodiscordant couples (one HIV-positive, one HIV-negative), including male-male couples and female-male couples. The researchers examined rates of HIV transmission from ART-adherent HIV-positive partners with undetectable viral loads to HIV-negative partners during sexual activity without a condom. The researchers across the studies found zero transmissions of HIV from the HIV-positive partner to the HIV-negative partner. In December 2018, the Centers for Disease Control and Prevention began supporting HIV treatment as prevention.
When talking with your patients about U=U, it’s important to emphasize a few key points:
1. U=U assumes patients are taking ART exactly as prescribed.
Missing even a few doses of ART can increase the HIV viral load, so it’s important to take ART exactly as prescribed, every day for it to be effective. Supporting people to take ART can include reminder apps, support networks, and behavioral counseling. People with undetectable viral loads should continue with routine follow up, management, and health maintenance, usually every 3-6 months after viral suppression is achieved.
Before relying solely on U=U for HIV transmission prevention, patients should both:
Be on ART for at least seven months
Have a confirmed viral load less than 200 copies/ml for at least six consecutive months
2. U=U does not prevent transmission of other STIs or prevent pregnancy.
It can be easy for patients and providers to forget that treating HIV doesn’t reduce transmission of other STIs or prevent pregnancy. The best way to reduce the risk of STIs is to use condoms with all sex, which includes oral, vaginal, and anal sex. Continue to screen all patients for STIs based on CDC guidelines, regardless of HIV status and offer STI testing based on history.
Patients not currently seeking to get pregnant should be offered birth control counseling and methods. Client-centered contraceptive counseling for people living with HIV requires knowledge of what ART medications they are using, since there are some caveats.
3. There are complementary strategies for serodiscordant couples.
Whether or not a person’s HIV viral load is undetectable, you should counsel the patient about condoms, pre-exposure prophylaxis (PrEP), and post-exposure prophylaxis (PEP) based on their history.
U=U is an exciting addition to the current line-up of HIV transmission reduction strategies currently endorsed by the CDC. U=U can improve the sex lives of people living with HIV and their partners. As a health care provider, even if you are not managing HIV treatment, knowing the how and why behind U=U strengthens your conversations with patients and improves the sexual health of all our patients, regardless of HIV status.
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