2.12 Viral load on and off treatment
Viral load when not on HIV treatment (ART)
When not on ART, your CD4 count is more important than viral load.
Even though ART is now recommended for everyone, the CD4 count still gives an indication of the urgency to start.
Viral load tests are still useful, but they are not as important at either predicting the risk of infections or when you should start treatment.
The one exception may be if your viral load is very high. This is because some HIV drugs are not recommended If your viral load is higher than 100,000 copies/mL.
Viral load when on treatment
If you are taking ART, viral load is more important than CD4 count.
This is because on ART, your CD4 count is probably already increasing.
Your viral load when on ART is the best measure of how long you can expect treatment to last.
If viral load gets to less than 50 copies/mL then ART is likely to last for many years. When viral load is this low, resistance usually only develops if you are late or miss taking your medication.
If viral load only gets down to a low level like 500 copies/mL, there is still enough HIV reproducing each day for resistance to develop to the drugs in your combination.
Viral load usually goes down by at least 90% (1 log) within the first few days of treatment, even though it is rarely measured this early. It usually drops by 99% (2 logs) within the first month. Most people reach undetectable (less than 50 copies/mL) within three months.
How quickly viral load becomes undetectable depends:
- How high viral load is when you start ART.
- How good you are are taking all your meds.
- Which drugs are in your combinations. Integrase inhibitors reduce viral load more quickly than other types of HIV drugs.
How often to use viral load tests? What happens if you do not have access?
How often viral load should be tested varies in different guidelines.
UK and US guidelines historically recommended viral load testing every 3-6 months when not on treatment, and every three months when on treatment. They also recommend a viral load test one month after starting or changing treatment.
More recently, in someone who has a high CD4 count and who is not on treatment, guidelines have recommended viral load testing every 6-12 months.
If you do not have access to a viral load test, your doctor will manage you based either on CD4 tests or on clinical symptoms.
Not having access to viral load tests should not be used as a reason to not use ART. Many countries do not have viral load tests in routine use, but still provide treatment effectively.
Last updated: 1 January 2016.