Healthcare providers should discuss U=U with all their HIV-positive patients

Healthcare providers should inform all patients with HIV they cannot transmit HIV to a sexual partner when their viral load is undetectable, argue the authors of  a strongly worded comment in The Lancet HIV. The authors note that despite overwhelming scientific data supporting the undetectable = untransmittable (U=U) message, significant numbers of healthcare providers do not educate their patients about U=U when telling them their viral load is undetectable.

“Providers caring for patients with HIV should universally inform their patients about U=U as part of their routine care,” write Dr Sarah Calabrese of George Washington University and Professor Ken Mayer of the Harvard Medical School and Fenway Institute. “Conveying benefits and risks surrounding any treatment is fundamental to patients’ decision making, and this HIV treatment benefit should be no exception.”

Four rigorous studies involving HIV serodiscordant couples have failed to find a single proven case of sexual transmission of the virus when the HIV-positive partner is taking antiretroviral therapy and has a stable undetectable viral load. The evidence supporting U=U is robust in both male-female and male-male couples. The World Health Organization (WHO) and more than 750 organisations worldwide agree that people with HIV whose viral load is stably suppressed cannot sexually transmit the virus.

However, recent research suggests that a significant proportion of healthcare providers are not educating their patients about U=U. An international survey involving more than 1000 providers found that only 77% of infectious disease specialists and 42% of primary care physicians communicate the U=U message when telling patients their viral load is undetectable. Reasons included disbelief (i.e. not accepting that U=U), a perception that U=U would undermine personal responsibility and concerns about patients’ behaviour and understanding.


Undetectable = Untransmittable (U=U)

U=U stands for Undetectable = Untransmittable. It means that when a person living with HIV is on regular treatment that lowers the amount of virus in their body to undetectable levels, there is zero risk of passing on HIV to their partners. The low level of virus is described as an undetectable viral load. 


Social attitudes that suggest that having a particular illness or being in a particular situation is something to be ashamed of. Stigma can be questioned and challenged.


A feeling of unease, such as worry or fear, which can be mild or severe. Anxiety disorders are conditions in which anxiety dominates a person’s life or is experienced in particular situations.


In HIV, usually refers to legal jurisdictions which prosecute people living with HIV who have – or are believed to have – put others at risk of acquiring HIV (exposure to HIV). Other jurisdictions criminalise people who do not disclose their HIV status to sexual partners as well as actual cases of HIV transmission. 

treatment cascade

A model that outlines the steps of medical care that people living with HIV go through from initial diagnosis to achieving viral suppression, and shows the proportion of individuals living with HIV who are engaged at each stage. 

“With evidence supporting undetectable = untransmittable (U=U) now overwhelming, providers should be routinely communicating the message to all of their patients living with HIV,” Calabrese and Mayer say.

The authors note that informing patients about U=U has numerous individual and public health benefits:

  • Encourage patients to start and adhere to antiretroviral therapy, and maintain an undetectable viral load.
  • Psychosocial benefits, enabling individuals to have intimate sexual relationships without fear, reducing internalised stigma and alleviating anxiety about the possibility of transmission.
  • Help reduce HIV incidence by encouraging engagement in the HIV treatment cascade.
  • Accelerate reforms in government policy and the law, especially concerning the criminalisation of HIV exposure and non-disclosure.
  • There is still unawareness and misinformation about U=U in the communities most affected by HIV, including gay communities. Increasing knowledge and understanding of U=U might reduce HIV-related stigma in the broader community, encourage testing and lessen anxiety about acquiring HIV.

The authors express concern that people who cannot access HIV therapy because of cost, criminalisation or discrimination will not benefit from U=U, exacerbating existing health inequalities.

"However, for the U=U message to be withheld from any person living with HIV is inexcusable, particularly in settings where treatment is accessible," they conclude.


Calabrese SK & Mayer KH. Providers should discuss U=U with all patients living with HIV. Lancet HIV, online ahead of print, 13 February 2019. (Full text freely available).