3. 9 Getting viral load to undetectable (less than 50 copies/mL)

The main goal after starting ART is to reduce viral load to undetectable.

It is not to to increase your CD4 count. It is not to protect your partners. It is not to improve your health. And it is not even to make you feel better. These are all important, but they are secondary goals.

An undetectable viral load prevents the risk of drug resistance. This means you can use the same ART for many years, rather than just a few months.

In 2023, about 95% of people starting ART in the UK get an undetectable viral load within six months.

Of course, ART will also improve health and increase CD4 counts.

But the main goal is to reduce viral load to undetectable.

How quickly should viral load drop?

Viral load should drop by at least 90% (1 log) after 1 month.

It should get to less than 50 copies/mL within 3 to 6 months.

However, a few people to take longer.

One exception

Sometimes it can take much longer to become undetectable, even with perfect adherence. 

This exception is if the low level viral load comes from a reservoir of sleeping cells. In this case, ART will still be working well and changing treatment will not make any difference.

This example might not be known by your doctor.

This can happen if someone is diagnosed very soon after infection. Also after starting treatment very early with a very high viral load.

HIV clinics can not test for this. It has to be interpreted based on very high adherence to a combination that really should work. See the report below for more information.

Viral reservoir can explain persistent low level viraemia with good adherence on ART

Last updated: 1 January 2023.