Q and A


How quickly should CD4 and viral loads change after starting ART?

After starting treatment how long does it take to see changes in you CD4 count and viral load?

How long does it take to get an undetectable viral load?



Viral load changes very quickly after starting HIV treatment (ART).

Viral load probably drops by 90% in the first few days and by 99% within the first 1-2 weeks.

How long it takes for viral load to become undetectable will vary. This depends on:

  • How high viral load was when you start treatment.
  • Which drugs are in ART. Integrase inhibitors reduce viral load faster than other types of HIV drugs.
  • Whether you take your meds as recommended. This means at the right time and the right dose.

Many people become undetectable or close to undetectable within a month and most by 3 months. If you start with a very high viral load (in the millions) it could take 6 months.

CD4 changes occur more slowly. Just as it usually takes many years for the CD4 count to fall when not on treatment, they take many months and years to see the full benefit of treatment.

As with viral load, the response will be related to the CD4 level when you start treatment. The lower it is, the more slowly it is likely to take to respond, and also the less likely that you will reach the high levels.

The higher yor CD4 count when you start, the more quickly it is likely to increase.

This answer was updated in January 2016 from a question first posted in September 2012.


  1. Lisa Thorley

    Hi Beveron.

    What was your husbands CD4 count when he started medication? What medication has he been given? Are you aware of what his viral load is, or what it was when he started medication?

    The following link will be of some help:


  2. Beveron

    Is it dangerous my husband CD4 count is 26 but he takes his meds more than 2 weeks..


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