Question

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.

301 comments

1. Rebecca McDowall • 9 May 2013

   Although it is unusual there are a few people who don’t see any increase in CD4 count. The most important thing when on treatment is that the viral load is undetectable- do you know if your husband has this checked by his doctor? How is his health in general?

2. Zuki • 9 May 2013

   Hi

   my hubby started taking arvs in 2008,his viral load was seating on -40 and now it is seating on 53 what could be the problem that its increasing what is he not doing right

3. Rebecca McDowall • 11 April 2013

   Hi Justyn,
   The only way to drop your viral load is to take ARVs. Are you currently on treatment?

4. justyn • 11 April 2013

   oh ya,its quite challenging and shocking.for example am 8months pregnant and when i went to check my cd4 en viral load as well,the results were reading that my cd4 count are 596 while the viral load is 10308copies/ml.en therefore i will not be allowed to breast feed because the chances are high of infecting the baby.
   Please advise how i can drop down the viral load so fast even after birth.

5. Rebecca McDowall • 13 October 2012

   Hi Sera, your CD4 count is very good. A ‘normal’ CD4 count is between 500-1600 for somebody without HIV. So you’re doing well. I can’t tell you what your viral load is. Viral loads and CD4 counts measure different things so one result can’t tell us the other. The only way to know your viral load is to do a viral load test.

6. sera • 13 October 2012

   I’ve a CD4 count of 945. What can my viral load be? I don’t have any symptoms and I weight 85kg and I’m 23yrs. Am I doing good?

7. Rebecca McDowall • 10 October 2012

   Hi Tom, I’ve replied to your question here

8. Tom • 10 October 2012

   Hi there

   I was diagnosed last week with HIV, it’s been a pretty tought few days since then. I’m 27, in good health, not unwell except getting colds and maybe ulcers in mouth. My initial test results came back today as cd4 count of 297 and viral load of 760,000. The viral load seems quite high and the cd4 count a bit low. I’ll be meeting with doctors next week once a resistance test has been done to see what treatment I can have.

   I’m quite worried about the viral count though, are there any common reasons as to why it may be this high? Also, upon starting treatment, I assume this will go down quickly and that hopefully my cd4 will go up to that of a normal person over a few years to 500? I’m quite scared at the moment as this is all new to me and has been a huge learning curve and a kick up the bum to sort my lifestyle out (eat healthy, exercise more etc). Any advise you can prove I would be grateful for. Thanks

9. Rebecca McDowall • 16 August 2012

   Hi Morgan,

   Do you know what your most recent CD4 count is?

   Gaining weight can be a good sign that treatment is working. How does your current weight compare to your weight before you were infected?

   Can you tell me more about the pain in your feet? This could be a sign of something called peripheral neuropathy, which can be a side effect 4T (and TB med isoniazid). More information about peripheral neuropathy can be found in our guide to side effects. If you think this is the type of pain you’re experiencing you should talk to your doctor and be given the switch d4T to a different drug.

10. Morgan • 15 August 2012

    I started taking ARV,s in 2010 when i suffered from tuberculosis, my weight then was 58kgs, now my weight is on 98kgs, i dont suffer anything except sore feet. My combination is stuvudine, lamuvidine and neverapine. Is the increase in weight showing that i am improving, the time i started medication, my CD4 was 86.