U=U: What's the Risk?

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U=U: What's the Risk?

by Mari Lowe, NP-C
April 15, 2019
A woman smiles at her phone

People living with HIV often have questions about the risk of passing the virus to their negative partners. Good news--recent research has shown that patients who use antiretroviral medications to maintain consistently undetectable levels of HIV are effectively unable to transmit HIV to their sexual partners. Commonly referred to as “Undetectable = Untransmittable,” or U=U, HIV treatment as prevention (TasP) is gaining traction as a method of 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:

How does U=U prevent HIV transmission?

If a person follows their medication 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. HIV treatment 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 treatment 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 male-male and male-female couples where one was HIV-positive and one was HIV-negative. 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.

For HIV to be untransmittable through sex, it’s important that:

1. To take medications exactly as prescribed.

Missing even a few doses of medication can increase the chances of passing an HIV infection to a sexual partner. So, it’s important to take these medications exactly as prescribed, every day for it to be effective. For U=U to successfully prevent the transmission of HIV, people need to be on HIV medications for at least seven months and their viral load needs to be undetectable for at least six consecutive months. Supporting people to take HIV medications can include using reminder apps and tapping into support networks. People do still need to check-in with a health care provider, usually every 3-6 months, even when their viral load is undetectable.

2. To remember that U=U does not prevent transmission of other sexually transmitted infections (STIs) or prevent pregnancy.

It can be easy to forget that treating HIV doesn’t reduce the chances of getting other STIs, like chlamydia, gonorrhea, or syphilis 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.

Whether or not a person’s HIV viral load is undetectable, you can decrease the risk of HIV infection by using condoms every time you have sextaking pre-exposure prophylaxis (PrEP), and post-exposure prophylaxis (PEP) as needed. 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.

May is “Talking is Power Month.” If you are a champion to a young person make it count and talk to them about sex and STIs. Just by sharing information and your experience you can help them to make better, safer decisions.

Mari Lowe, NP-C, works as a family nurse practitioner in Washington, DC, serving in respite care and medical outreach for people experiencing homelessness. She previously spent several years incorporating sexual and reproductive health into primary care at Unity Health Care. In her free time, you’ll find her reading the latest non-fiction book or practicing yoga.