Undetectable = Untransmittable

Undetectable = Untransmittable (U=U) is a message used in HIV campaigns. It implies that if someone has an undetectable viral load, they can not transmit the HIV to others through sexual medium.

In other way, when a person living with HIV is actively taking HIV drugs and their viral load stays at undetectable levels (< 200 copies/mL), that person cannot transmit HIV to a sexual partner who is HIV-negative.

There have been many clinical trials that have established the validity of U = U and it has been scientifically proven. U = U is also used as an HIV prevention strategy, meaning that if someone is undetectable, they can not pass it further and hence, prevents the virus from spreading. This is known as Treatment as Prevention and abbreviated as TasP.

U=U campaign origins

The U=U campaign was launched by the Prevention Access Campaign in early 2016 from a Scientific Consensus Statement. It aims to change what it means to live with HIV by raising awareness and dismantling the stigma around HIV, improving the quality of life of those living with it in order to end the epidemic.

How it works

• Become undetectable: This can take up to 6 months after starting HIV medication. Your health care provider will perform blood tests and let you know when you're undetectable.


• Stay undetectable: Get a second undetectable test result at least 6 months after the first. Continue to take your HIV medications daily and visit your health care provider regularly. They will monitor your blood tests to make sure you're still undetectable.

As you can see in the picture, after starting the treatment, the level of HIV in the blood will decrease and eventually it will be less than the undetectable level of 200 copies per ml. This process may take up to 6 months. If the treatment continues and the second 6-month test remains undetectable, we tell the person to continue the treatment and regular tests and live like a normal person. :-)

How HIV Treatment Makes U=U

With any virus, the likelihood of transmitting it depends on the amount of virus in your body. HIV drugs prevent the HIV virus from reproducing (making copies of itself). When a combination of HIV drugs (your drug regimen) is working, the viral load usually goes down quickly after starting the drugs and finally they become "undetectable". It is true that the current treatments cannot destroy all the viruses in the whole body at once and free a person from the need of medicine (the person must use regular medicine for the rest of his life), but because the number of viruses in the blood has decreased mostly, The probability of transmission is almost zero.

Scientific evidence

(What is science?)
In 2016, the same group published the results of the PARTNER-1 study. In this study, the conditions were far more specific and the question more targeted. A total of 1,166 serodiscordant heterosexual and MSM couples were included. In all cases, the person living with HIV had a plasma viral load of less than 200 copies per mL of blood. The couples also reported not having used condoms during sexual intercourse. After 36,000 instances of intercourse in heterosexual couples and 22,000 in MSM couples, there was no related transmission of HIV. For this reason, it was decided to continue studying more encounters and more couples, because even the number studied did not have enough statistical power.

In 2019, the additional results of PARTNER-2 were published. In this study, serodiscordant MSM couples were analysed in which the person living with HIV had had an undetectable viral load for six months or more. 76,991 sexual acts without condom use were documented with no related transmission. This study is therefore the one that allows us to affirm that the risk of sexual transmission of HIV is 0 when the person with HIV has an undetectable viral load for 6 months or more.

Taking HIV medications also helps people living with HIV feel better because it keeps their viral load low. A low viral load means a healthier immune system, which in turn prevents the person from progressing to AIDS.

According to the U.S. Centers for Disease Control and Prevention (CDC), nowadays, if a mother takes HIV drugs while pregnant and has an undetectable viral load, the chances of transmission to her baby can be less than one in 100.

Sharing the message of U=U is part of a strategy to break down HIV stigma, provide hope, improve the lives of people living with HIV, and move closer to ending HIV as a worldwide epidemic.

For many, the fact that an undetectable viral load also acts as a barrier to HIV transmission has been a difficult message to accept. We know that, because shifting in attitudes, beliefs, and behaviors after decades takes time, but awareness is increasing and you and as always I are doing our best.

Sources: thewellproject / health.state.mn.us / wikipedia

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