Question
How quickly does viral load drop on treatment?
5 July 2020. Related: All topics, CD4 and viral load, Starting treatment.
I’ve been trying to understand on average, the daily rate of decrease in viral load following initial treatment.
I’m guessing that this changes over time and varies from case to case according to the chosen treatment, CD4 count and viral load level and possibly other factors.
However, supposing that the viral load is around 100,000, the CD4 count is around 400 and the treatment used is Atripla, could anyone please let me know the expected % decrease of viral load level per day at least within the 1st month of treatment?
Thank you for the help.
Answer
All HIV combinations (ART) starts working from the first dose.
Viral load is usually reduced by 90% (also referred to as 1 log) within the first few days. It then continues to fall but not as quickly (see below) until it becomes undetectable.
A log is a number mulitplied to the power of 10. So with a viral load of 100,000 copies/mL, a 1-log reduction would bring your viral load down to 10,000 copies/mL and a 3-log reduction would reduce it to 100 copies/mL. (See this factsheet).
You are right that individual factors will lead to difference rates of viral load reductions. These include:
- How high your viral load was when you start ART.
- The medicines in the combination (integrase inhibitors casuing the fastest drops).
- The drug levels of this meds (related to adherence and how they absorb and processes drugs).
- Good adherence – not missing doses.
UK and US guidelines recommend that your viral load should be undetectable within three months. However, many people achieve this within the first month, especailly if they are using an integrase inhibitor.
Some people take longer, especially if their viral load is very high when they start treatment.
Lots of studies have reported detailed early responses ART, including for efavirenz-based combinations like Atripla.
This decline is often referred to as having three main phases.
The first phase is very rapid – referred to in some studies as being the first few days and in others as within the first two weeks. This is where the actively infected CD4 cells are targeted. CD4 cells infected with HIV only live for a few days and when you start treatment this virus and these cells are quickly reduced.
This results in a viral load drop of perhaps 99% (2 logs) within two weeks.
The second phase, out to the first month is slower, as it is working on cells that live longer. This can easily reduce viral by another 90% (another 1 log reduction). In people with very high viral loads when they start treatment, this second phase may continue for longer until viral load becomes undetectable.
Some researchers also talk about a third phase decline which occurs even more slowly and gradually once your viral load is undetectable.
This relates to a reduction in the levels of infected CD4 cells that are latent (or resting). This pool of cells only slowly decreases over time.
This link is to an early study describing the two-phase viral load reductions.
This answer was updated in July 2020 from a question first posted on 15 September 2012.
Hi I’m about 37 weeks pregnant and I’m HIV and my viral load is about 90 .Is there a big chance that my baby could as be HIV +
Hi Joseph,
Other than your CD4 count, do you know what your viral load is?
When you started ARVs, you started with a very low CD4 count. Though it’s still low, a rise from 49 to 111 is good progress. In time, it will get higher.
Hi! I Started to take my ARVs in August 2018. And my CD4 was 49. In March 2019, my CD4 was 111. I want to know that I am coming good or it’s coming slow. I didn’t check for this month of June 2019.
Hi Muhle,
How long have you been taking HIV meds? When did you have the HIV positive result, and what did the nurse say about the result?
It usually takes about three months to get to undetectable after starting HIV treatment (ART). What did the doctors say when you gave birth to your baby? Were you taking HIV meds then?
Please let us know.
Can I possibly be HIV+ if my cd4 blood count was 500 while I was six months pregnant and had not started medication yet and by the that time my nurse did not check my viral load so three months down the line after giving birth and taking the medication my viral load is lower than detectable what this actually mean and could this be a false diagnosis
Hi Sli,
If your viral load is high and you’re on ARVs this is an indication that the meds are’t working. You’re going to need to talk to your doctor and ask them about other combinations. Please see here: http://i-base.info/guides/changing
I started arvs but I stopped for some period of moths then started again but now my viral Lord is very high will it ever work or what can I do
Hi Oscar,
If your viral load isn’t dropping this means that your meds aren’t working. Your going to need to talk to your doctor about changing to another combination. Please see here for more info: http://i-base.info/guides/changing
Am on ART for 4 yrs but my virial load is is not dropping. Am taking medic as per instructions. What can be the cause?
Hi Sonto,
To know if the tribuss is working like it should do, you’ll need to have a viral load test. This will let you know how you’re doing.
Yes you can take TB meds when also taking ARVs. Info about side effects of TB medication can be found here: https://www.nhs.uk/conditions/tuberculosis-tb/treatment/