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. Mr too • 29 November 2018

   Hi friends l have viral lod 823 how can halp to reduce numbers of it.

2. Roy Trevelion • 27 November 2018

   Hi Guitasius,

   That’s great news. Please see U=U.

   But some doctors already think that waiting for a month once you’re undetectable might be fine. That’s until guidelines are reviewed and hopefully updated. Please see this Q&A for full info on your question.

3. Guitasius • 27 November 2018

   my viral load cannot be detected already in my fourth month on medication, my wife is negative, can i still use a condom ? is there any possibility that they can be deteced again?

4. Lisa Thorley • 23 November 2018

   Hi Thash,

   If your viral load is undetectable, then there’s no risk of transmission. Please see here: http://i-base.info/u-equals-u/
   A viral load becomes undetectable if there is treatment failure or if someone doesn’t adhere to their medication. It will be detectable usually within a week.

5. Thash • 23 November 2018

   Good day

   I want to query, my viral load was undetectable recently. I always use protection. The thing is I had two nights where condoms blasted and manage to notice that then I changed them. But now I am stressed because I do not want it to transmit to anyone. I want to know how long does viral load take to be detectable? How many unprotected sex to have in order for viral load to be detectable?

6. Roy Trevelion • 21 November 2018

   Good Day Grace,

   Have you been on HIV treatment long? You can see from this page in ART in Pictures what happens when you start ART. Viral load can sometimes be very high when starting treatment. And it can take several months to get to undetectable.

7. Grace • 21 November 2018

   Good day,
   i was at the clinic yesterday and was told my viral load is very high, 3,600, am on treatment as well, how soon can my viral load drop to below hundred before 15 th january 2019 for check up. Thanx Grace

8. Roy Trevelion • 21 November 2018

   Hi Tshweni,

   Congratuations on the news that you’re going to have a baby. It’s great that you’ve been on ARVs for 6 years with a viral load of 0. Having an undetectable viral load when you deliver can help reduce the chances of your baby being HIV positive to zero.

   Do you mean you haven’t seen an obstetrician yet? It’s a good idea to fix up an appointment soon.

   Your BF has not been at risk of HIV since you became undetectable. Please see undetectable = untransmittable (U=U). U=U means that HIV cannot be transmitted to your partner even if you don’t use condoms

9. Tshweni • 21 November 2018

   Hi Lisa

   i have been diagnosed for about over 6 years now and i have been on ARV’s ever since. my viral load is -0. I then developed epilepsy (now on Epilem 200mg) for about 3 years now this could be due to the Duromines i was over taking. My condition is fine.

   Now I am 4 months and weeks pregnant, my BF doesn’t know about my status and I haven’t seen an oncologist. What are the medication or Supplement’s I should be start taking (For prevention of mother to child) and what are the chances of my BF being positive because I am scared to persuade him to go and test; he will be suspicious. Though he needs to know and be aware.

10. Roy Trevelion • 20 November 2018

    Hi Dudu,

    Accidents like this do happen. But it’s not ideal. However, you’re back on your meds now. What are your taking?

    Having a treatment break can sometimes mean there is viral rebound. You can talk to your doctor about this and ask for a viral load test. If there is viral rebound you can ask about drug resistance and switching to different meds.