Yet misunderstandings about transmission risk persist, finds a large NIH-supported study.
A variety of antiretroviral drugs used to treat HIV under the motto “U = U.” NIAID
Extensive evidence from HIV prevention research studies has firmly established that “undetectable equals untransmittable,” or T=T. This means that people living with HIV who achieve and maintain an undetectable viral load (the amount of virus in the blood) by taking antiretroviral therapy (ART) as prescribed do not sexually transmit HIV to others. The U.S. Centers for Disease Control and Prevention estimates this strategy to be 100% effective against sexual transmission of HIV.
Now, a new study of nearly 112,000 men who have sex with men in the United States has found increasing acceptance of the U=U message in this population. Overall, 54% of HIV-negative participants and 84% of HIV-positive participants correctly identified U=U as accurate. The study was supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. Results of the study were published online today in the Journal of Acquired Immune Deficiency Syndromes.
“U=U has been repeatedly validated by numerous studies as a safe and effective means of preventing sexual transmission of HIV,” said Anthony S. Fauci, MD, Director of NIAID. “The increased understanding and acceptance of U=U is encouraging because HIV treatment as prevention is the foundation of efforts to end the epidemic in the United States and around the world. This public health message has the power to reduce stigma, protect the health of people living with HIV, and prevent sexual transmission of HIV to others.”
Researchers led by H. Jonathon Rendina, Ph.D., MPH, at Hunter College of the City University of New York, collected data from secure online surveys promoted on social media and mobile dating apps from November 2017 to September 2018. Responding to responses from self-identified sexual minority men, the researchers found that approximately 55% of participants responded “completely accurate” or “somewhat accurate” to the question, “Regarding HIV-positive individuals transmitting HIV through sexual contact, how accurate do you think the slogan Undetectable = Cannot be transmitted is?”
Acceptance of U=U was much stronger among participants who reported they were living with HIV (84%) compared with HIV-negative participants (54%) and those who did not know their HIV status (39%). The researchers found that acceptance of U=U had increased over time when comparing the data to results of a similar study by the same group that looked at data collected in 2016 and early 2017. Among the 12,200 sexual minority men surveyed at the time, only 30% of HIV-negative participants and 64% of participants living with HIV agreed that U=U was either comprehensive or somewhat accurate.
In the current study, HIV-negative participants who reported seeking HIV testing and prevention services, as well as those who took daily pre-exposure prophylaxis (PrEP), were more likely to believe that U=U was accurate. These findings suggest that uptake of U=U correlates with more frequent interactions with HIV prevention services. Among HIV-positive respondents, those who reported excellent ART adherence were more likely to agree that U=U is accurate compared with those who reported “less than excellent” adherence or did not take ART at all.
The online survey also asked respondents to use a graduated scale from 0% (“no risk”) to 100% (“complete risk”) to rate the risk that a man whose HIV was undetectable would transmit the virus to his HIV-negative partner through condomless insertive or receptive anal sex. While studies confirm that a person whose HIV is suppressed does not transmit the virus through sexual activity, only 10% of all respondents rated the risk of transmission as zero when the insertive partner has undetectable virus. Similarly, only 14% of respondents rated the risk of transmission as zero when the receptive partner’s HIV is undetectable.
Among those who agreed that U=U was “completely accurate,” only 31% and 39% believed that the risk of transmission is zero when the insertive or receptive partner, respectively, has undetectable virus. However, acceptance of U=U was associated with a lower perceived risk of HIV transmission through any form of condomless anal sex.
“A growing number of sexual minority men believe U=U is accurate, but our data suggest that most still overestimate the risk of HIV transmission from an undetectable partner, which may be because people have trouble understanding the concept of risk,” said Dr. Rendina, the study’s lead author. “All published studies point to undetectable viral load as the most effective method to date for preventing sexual transmission of HIV, but most of our messaging has focused on the risk level being zero rather than describing it in terms of effectiveness, which is how we usually talk about condoms and PrEP.”
All data collected in the online survey were confidential and self-reported. Study participants represented all U.S. states and were of diverse races and ethnicities, including 14% Black and 24% Latino. Participants ranged in age from 13 to 88 years, with a median age of 32 years. About 79% identified as gay, 18% as bisexual, and 3% as queer. About 1% of respondents identified as transgender.
Earlier this year, Dr. Fauci and colleagues wrote about the strength of the scientific validation for HIV treatment as a prevention strategy and U=U in a JAMA commentary. The efficacy of treatment as prevention was first verified on a large scale by the NIH-funded HPTN 052 clinical trial, which showed that no linked HIV transmissions occurred between serodifferent heterosexual couples when the HIV-positive partner had a durably suppressed viral load. The PARTNER 1 and 2 and Opposites Attract studies subsequently confirmed these findings and extended them to male-male couples. As described by the authors of the current study, the independent nonprofit Prevention Access Campaign launched the U=U slogan in 2016 to promote awareness of these scientific findings.
It is important to note that U=U refers only to the prevention of sexually transmitted HIV; condoms are still needed to prevent the transmission of other sexually transmitted infections.
Referencia
H Rendina et al. Increasing acceptability of Undetectable = Untransmittable but widespread misunderstanding of transmission risk: Findings from a very large sample of sexual minority men in the United States. Journal of Acquired Immunodeficiency Syndromes DOI: 10.1097/QAI.0000000000002239 (2019).
At: https://www.nih.gov/news-events/news-releases/gay-bisexual-men-increasingly-agree-hiv-undetectable-equals-untransmittable