Q and A

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

Answer: Simon Collins

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.

301 comments

  1. Mike •

    Hi,

    I had been feeling sick for over 6 months and on February 24th I was told that I was HIV positive. As you all know this was a huge shock to me and I felt as though my world was ending. Just a few days before I received the wonderful news that I got the promotion of my dreams. This couldn’t be a worst time to get this diagnosis, then again is there ever a good time?

    Anyways I started taking Atripla March 1st and at first I thought everything was fine but I started feeling sicker and sicker, towards the last couple of weeks of the month I was in bed most of the time with dizziness, nausea, and very depressed. After that my parents took me to see another specialist who switched my medication to Odefsey, I’ve only been on it for a week and some things has gotten better but not everything.

    I’m able to eat again and I’m not going to the bathroom as much anymore but I still feel very tired, since then I’ve gone back to work but I’m not as quick as I was and towards the end of the day I’m just tired. I know that it’s only been a week since I started the new medication but I thought I would feel better by now. Is this normal? Should I expect to feel like my old self or should I just get used to the fact this is how I will feel moving forward in life? I’m a social person and lately because I feel weak I haven’t even been able to do things I enjoyed such as meeting friends for dinner and drinks.

    Sorry about the long message but the only people I talk to about this are my parents and doctors. They keep saying I’ll be much better but after more than a month and two different medications I still don’t feel myself.

    At the end of the day I would just like for someone to share with me their experience with Odefsey, all I find online are the negative side effects of the medication and I’m worried that I’m getting in my head and think that I have all the negative side effects.

    Thanks for the help

  2. Lisa Thorley •

    Hi Melissa,

    If you say you’re losing weight, but when you go to the clinic you aren’t. Then I’m not sure why this may nor may not be happening. Have you brought this up with your doctor? Also how much weight do you think you’ve lost?

  3. Melissa •

    hi I have started my treatment this year but I am losing weight but am very energetic but when I go to the clinic my weight is still the same wat could cause that thank you

  4. Lisa Thorley •

    Hi Lindi,

    Diarrhea can be caused due to all sorts of things. Therefore, it may have nothing to do with you being HIV positive. This is something that you should talk to a doctor about.

  5. Lindi •

    Hi I have been on ARV’s since 2014. I have never stopped taking my pills,but now iI started having diarrhea. I went to hospital and they gave me medication to stop. I have lost weight and most of the time I get stomach cramps. My CD4 count was 840, adn I was undetectable in sept 2016. Now I’m confused, the nurse told me not to worry, but I can feel my body isn’t well.

  6. Lisa Thorley •

    Hi Nothile,

    Being diagnosed with HIV can be a shock. Try to slow down, and take your time. You’re going to be OK. Do you have anyone that you can talk to?

    Its common to feel anxious when starting meds. However, ART is very good and the side effects aren’t like they used to be. So no, you won’t get a buffalo hump. For more about starting meds, please see here:

    http://i-base.info/guides/starting

    The common side effects of odimune, (a generic of Atripla) are discussed here:

    http://i-base.info/guides/1561

  7. Nothile •

    Hi. I have just found out that I’m HIV positive and my doctor put me on odimune. Just want to find out, does it make a buffalo hump? I’m very scared.

  8. Lisa Thorley •

    Hi Lucia,

    Because your viral load is 42 copies, this means that you’re undetectable. This is important because it shows that the meds are working.

    With regards to your CD4 count, its important to know that they can and do fluctuate. This meaning that if you were to have it tested today that it may be much higher. For more info please see here:

    http://i-base.info/qa/424

    http://i-base.info/qa/424

  9. Lucia •

    Hi I’m Lucia I stated my ARV’s in July last year. In January I went for a blood test, my CD4 count is 308 but first time it was 310. My viral load is 42 copies.

  10. Lisa Thorley •

    Hi Amanda,

    How are you coping with your diagnoses? Are you getting any support?

    WHO recommend that everyone who is positive should be on meds. This includes people who have a high CD4. Therefore, if you feel that you are ready, then you should start them. For more info on beginning meds please see the following:

    http://i-base.info/guides/starting

Comment

Your email address will not be published. Required fields are marked *