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.
I am on treatment for about a year now and the first time I checked for viral load, it is about 11,000. My doctor said the timing for taking the med is not good.
1st is this load too bad?
2nd if I take the timing serious, will this improve within the next 3 months?
Hi Babs,
Isoniazid is effective against TB. What ARVs are you taking Babs? It can be complex treating TB and HIV so it’s a good idea to talk to your doctor to check that these drugs don’t interact. You can also ask about whether the TB is active and where in the body it might be.
And it’s important that side effects like these are checked out by your doctor too. So that you can find out what’s causing them.
Can one with hiv take isoniazid? I was given this as a protection against TB but since I started taken it for about a week plus now, it makes me feel feverish and my eyes getting hot behind it.
Hi Isaac,
As you know, you have to wait 28 days for your HIV test after finishing PEP. This is because PEP can delay infection rather than stop it. There’s more info on PEP here.
I took PEP but not ready to do post test. I had unprotected sex with my girlfriend, it’s possible da she can test hiv positive?
Hi Neville,
Getting your viral load down to 66 from over 100,000 means that your HIV treatment works very well.
Being undetectable on treatment (ART) means that HIV is untransmittable. However, the Partner study showed that there were zero transmissions of HIV after couples had sex over 58,000 times, without using condoms, when the HIV positive partner was on ART. The cut off for undetectable is usually 50 copies, but the VL cut off for Partner was 200 copies.
An HIV test will always be reactive even if you’re undetectable. So all HIV positive people get a reactive result, even when undetectable.
Can I infect a person when I have a viral load of hiv vl 66. My results doesn’t show if it’s reactive or non reactive. Give an understanding of what does it mean. Before I started treatment my viral load was 111000.
Hi Sol,
Info about ARVs and how they work can be found here:
http://i-base.info/guides/starting
how does the cd4 recover with the arv intake
Hi Ntobeko,
Unless we have the results there isn’t really anything that we can comment on. What was your viral load before you changed regime?