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Sexual health and LGBT population
Living with HIV
Post-exposure prophylaxis (PEP)
Not only is it important to be aware of the status of your immune system via the CD4 cell counts (please refer to the section What are CD4 cells?) but also the quantity of HIV virus that is present in your body.
You will recall from the previous section that the primary goal of HIV virus is to reproduce itself. The viral load test will permit you and your doctor to measure the quantity of HIV virus present per milliliter of blood. These results help to assess the activity level of the virus and your immune system. When the viral load is extremely elevated, HIV is actively reproducing and your immune system may be having trouble bringing it under control. When the viral load is low – the virus may be relatively inactive and/or your immune system may be efficiently managing the infection (even without medications early on in the infection).
Viral load results permit your doctor to evaluate the rate of progression of your infection. In summary: the greater the viral load, the faster your infection may progress (greater numbers of CD4 cells destroyed and your bone marrow can’t pump out enough new cells to compensate) and the lower the viral load, the slower the infectious process (fewer CD4 cells destroyed and your bone marrow is able to compensate for the amount of destruction incurred). The viral load also permits the evaluation of your response to treatment (please refer to the section How do I know if my treatment is working?).
Viral load results vary greatly from one individual to the next. The viral load may fluctuate widely within the same person on the same day. Results can be as low as below 50 (termed undetectable in the blood – and this at times even without medications) up to levels in the millions of copies of HIV per milliliter of blood. The greater the viral load, the greater the activity and reproduction level of HIV thus increasing the risk of a progression in the weakening of your immune system. Of note: There are ALWAYS exceptions to the rules – if you have concerns pertaining to your personal results – speak with your doctor!.
When the viral load rises above the level of 100,000 copies/ml of blood, the virus is considered to be actively reproducing thus increasing the risk of a rapid decline in CD4 cell counts responsible for the progressive weakening of your immune system. (Be careful!! High viral loads do not always result in rapidly declining immune system status – there are always exceptions to the rules).
A viral load below the level of detection indicates an extremely low quantity of HIV virus in your blood. Current laboratory testing in Quebec and Canada permits the detection of HIV down to the level of 40 copies/ml of blood. When your physician tells you that your viral load is undetectable it means that there is so little HIV virus circulatin freely in your blood that currently used machines are unable to detect its presence in the blood. Undetectable is a great thing – it means there is very little virus able to destroy CD4 cells and thereby enables your body (bone marrow) to slowly rebuild your immune system.
It is important to understand, that while your viral load is « undetectable », this does not mean that you no longer have HIV in your system. Unfortunately, it is currently impossible for currently available medications to completely eliminate HIV from the body (please refer to the section Why are treatments unable to completely erradicate HIV from the body?). Despite an undetectable viral load you are still infected with HIV. In addition, an undetectable viral load in the blood does not necessarily correspond with the level of HIV or viral load in other parts of the body and/or biological secretions from the body. Despite an undetectable blood viral load, there may be detectable virus in vaginal secretions, pre-ejaculate (pre-cum), ejaculate (cum) and maternal milk (breast milk). The bottom line is that even if you are “undetectable” you are still able to transmit HIV to your sexual partner.
As with the case of CD4 test results, it is important to place the results into the context of your trends – an isolated result is like a snapshot of one moment in the life of the HIV infection process. Given the great degree of fluctuation in results – comparing results and determining the trend is essential. Of interest – viral load results may vary as a result of events that your body is subjected to: recent vaccination, recent infections, excessive recreational drug use and extreme stress may all have an impact on results (increased viral loads in these examples). From time to time there may be laboratory error – this is important to remember when your results deviate greatly from your typical result trend. When results are unexpected – your physician may decide to repeat the tests thereby confirming lab error or true results. Decisions and modifications regarding treatment intervention should never be made based on a single laboratory result – particularly if the result is unexpected for you.