What does ‘Undetectable’ mean?

Someone who is undetectable means they are HIV Positive but that their viral load is so low (200 copies of HIV or less per millimeter of blood) that they cannot pass on HIV to anyone else by any means.

How do you become Undetectable?

You can can achieve an undetectable status when you have been on effective treatment (anti-retroviral therapy) anywhere between one to six months. The GUM clinic should inform you of when you’ve achieved undetectable status. They usually check your viral load every six months once you’ve been diagnosed as HIV Positive.  It’s important that you continue to take your medication regularly as prescribed to maintain your undetectable status.

How can you lose Undetectable status?
You can only lose your undetectable status if you don’t take your regular medication for several weeks. You can regain your undetectable status within one to six months by adhering to your daily regime of anti-retroviral therapy.

What medication does someone take to become Undetectable?
Antiretroviral Therapy (ART) is a drug that reduces the amount of HIV in your system until it becomes undetectable, and helps you stay healthy!

Can I get HIV from someone who is Undetectable?
If your sexual partner has been taking their regular medication and is undetectable – you won’t contract HIV regardless of their gender identity, sexual orientation or the kind of sex they choose to have.

Do I need to go on PrEP if my partner is HIV Positive and Undetectable?
Nope! You are actually safer from contracting HIV with a partner who is HIV Positive and Undetectable than a partner whose HIV status you do not know.

Does U=U work for all types of sex?
Yes! Studies (i.e Partner 1 & Partner 2) were conducted on both homosexual and heterosexual couples, and not one case of HIV was transmitted.

What if I forget/struggle to take my medication?
It is vital that you keep to your regular medication schedule. The occasionally missed, forgotten or late doses won’t affect it, and it won’t affect your viral suppression. But if you can’t remember to take your medication regularly, you should see your clinician and check
the viral load. If in doubt, wear a condom and get checked.

The Statistics.
In 2019, 98% of people living with HIV in the UK are on antiretroviral therapy (ART) and 97% of those have an undetectable viral load – this means that if they are taking their prescribed medication, they can be confident not to pass on the virus to their sexual partners
as there is a very low risk of viral load rebound

The PARTNER 1 (2016) Study looked at 58,000 couples. One partner was HIV positive and the other was negative. The study followed the couples for a year, and found zero transmissions of HIV whilst having unprotected sex.

The PARTNER 2 Study (2019) similarly followed 782 couples with one positive partner and one negative and found zero


Whilst many people achieve undetectable status through effective regular medication, not every person who is HIV Positive will. Just because someone is HIV Positive with a detectable status does not mean that they are not equally worthy of dignity, respect and love! Please do not feel that you cannot have sex or even a romantic relationship with someone who has a detectable viral load. Remember that  you can easily protect yourself against contracting HIV by using condoms (you can order free condoms & lube here) or taking PrEP.


“It’s important that in promoting U=U we do not split the community between those who are undetectable and those who are not. We must ensure that people don’t feel their value as an individual is determined by whether they can pass the virus on to others. Human rights are not dependent on viral load. ”

Charlie Alderwick (National AIDS Trust) 2018

For more information, visit:
●  Frequently Asked Questions about U=U (Terrence Higgins Trust)
●  ‘Can’t Pass It On’ online training for professionals  (Terrence Higgins Trust) 
●  ‘Can’t Pass It On’ campaign (Terrence Higgins Trust) 

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