Question

A question on viral load and changing one of the compounds of the combination

15 June 2009. Related: All topics, CD4 and viral load, Changing treatment, Cure.

HI,

I have some questions.

My first question is that I have been on ART and my viral load has gone down to less than 40 after 3 months of medication. Then over a year it has been less than 40. Why has it stayed that way for a long time? Can’t it go down to zero at least in the blood?

My second queston has to do with the fact that in your answers to some questions you said that in semen VL takes longer to be undetectable. But how long? When does it go down to undetectable level, equally as in the blood?

My third question is I have been taking AZT+3TC and effavirenz for more than a year. The treatment has been effective, since my VL has been less than 40. Now, my doctor says I am to change the AZT to tenofovir. What will be its effect on my VL? Will my VL continue to be undetactable? If not, after checking, can I come back to the AZT?

Thank you for your cooperation.

Answer

Answer: Simon Collins

Undetectable viral load means that the test is not able to find any virus, because its ability to detect virus is limited.

The tests that are used commonly in the UK now can detect to 40 copies/ml and above. There are still labs that may use lower limit of 50. So, undetectable means that you have less than 40 viral copies per unit of blood. This, however, does not mean that you do not have any virus in the blood. It only means that the test cannot detect it, as it can measure only as low as 40 and above.

Even if someone gets to 0 copies in the blood, this does not mean that the person has been cured, as the virus stays in certain parts of the body, called ‘sanctuary places/compartments’ and it can reactivate from those. That is one of the reasons why it is important to be adherent to the therapy and not to have breaks in taking it.

To your second question, there is a dicordance in the VL results in the blood and the semen and it is very well documented. What is not well documented is what time it takes in different people to have their VL in the semen undetectable (if ever), and this can be explained with the fact that the clinical relevance of semen testing is very limited, while the VL tests are still expensive.

Anyway, undetectable VL in the semen does not mean that one is uninfectious either.

Finally, it is good that the AZT from your combination is switched to tenofovir. AZT is more linked to long-term side effects like lipodistrophy, anaemia, etc. Your results will be closely monitored and if you are not happy with them, you will have the option to go back on AZT.