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 Lisa
Why I am so much worried about this is because I am a discordant couple and we plan to have baby the normal way.
Thou my wife is yet to start PREP and I feel some level of weight loss.
Hi Emmanuel,
The antibiotics that you’re taking won’t cause any interactions with your ARVs. How long have you been on meds for?
ARVs don’t cause problems with a mans fertility and or their semen.
Hi Lisa
I was given Tenofovir Disoproxil Fumarate/Lamivudine/Efavirenz to be taken once everyday preferable at night and Septrin 900mg to also be taken once everyday which I normally take in the morning. Hope the HIV drug is enough to reduce my viral load to undetectable level. When I started taking them the side effect was dizziness and tiredness to do anything but gradually it is subsiding. Just that it makes me to eat a lot and go hungry almost every time.
The antibiotics I was given are Zimilat which is a combination of Amoxicilin+potassium clavulanate, Afretaron, Doxycycline pexin and 2 others drugs that I don’t no the name. I wrote to I base since last week that I was given the drug to no reply so am actually on the 5th day of taking the medication which should last about 7 days.
Hope I am not harming myself and also what could have cause the absolute reduction of the viscosity of my semen under one month on ART.
Hi Emmanuel,
What meds are you taking for the HIV? What antibiotics have you been given?
Hi Lisa
I was recently diagnosed with HIV and have started ART immediately. Thou recently I found out that my semen quality have reduced after a perfect semen analysis a month before I started treatment. I was given drugs by my doctor which from my researches are antibiotics. Will these drugs affect or cause any form of resistance.
Hi Ianre,
Your CD4 is increasing well, and you’re undetectable. This is great news. You’re in control of your HIV.
My CD4 was 128 from there to 198 then my CD4 is 238 and viral 20 what do you have have to say.
Hi Alicia,
The example given was just an example. As the above post explains, ideally someones viral load should become undetectable within 3 months. However, this can be longer especially if someone starts with a very high viral load.
Just a quick question with regards the viral load. If a person’s viral load is 23000 and their CD4 is 808 and they have been on Medications from the time they found out the virus was present so approximately over 2 months they have been on the following: tenofovir; atazanvir and ritonavir. Due to study (i know it may vary) but all things considered just as you explained in a previous example with 100000 can you do the same please with that of viral load of 23,000.
Thanks in advance
Hi Steve,
If you’ve been on meds since last November and your viral load is still detectable this is a sign that the meds that you’re taking aren’t working like they should be doing. Therefore, this is something that you will need to talk to your doctor about. For more info about changing meds, please see here:
http://i-base.info/guides/changing