Treatment Review, Issue #29 * Winter 1999
There are now 13 anti-HIV drugs available by prescription.
Combinations of anti-HIV drugs are now commonly called HAART,
which stands for Highly Active Antiretroviral Therapy. HAART
combinations usually include three or four anti-HIV drugs.
Studies have shown that HAART can work well in people with an
AIDS diagnosis or symptoms of HIV infection. However, for
people earlier in their disease who don't have symptoms of HIV
or AIDS, the best time to begin HAART is not certain.
One thing is quite clear: you don't necessarily need to take
HIV drugs just because you're HIV positive. HIV causes illness
by damaging the immune system. Measuring the T4 cell count
gives an idea of how the immune system is doing, and can also
help decide if anti-HIV drugs are needed. The other important
test is called the viral load test. The viral load test
measures the amount of HIV in a blood sample.
Measuring both the T4 cell count and the viral load can help
work out if you're at risk for disease progression over the
next few years. In one large study, for example, a person who
started with T4 cells between 350 and 500 and a viral load of
less than 14,000 copies had a very low risk of disease
progression over the next three years. Their risk of
progressing to a diagnosis of AIDS within three years was about
5%, or a 1 in 20 chance. For people in this position, waiting a
while to plan a treatment strategy is not likely to put your
health at risk.
A person who started the same study with a T4 cell count in the
same range (350-500) but a viral load of over 110,000 had a
much greater risk of disease progression. Their risk of
progressing to a diagnosis of AIDS within three years was close
to 50%, or a 1 in 2 chance. Most doctors would strongly
recommend treatment if you're in this situation.
If you're risk of disease progression is low, waiting to start
treatment can be a good strategy for a number of reasons:
* You may benefit from new information about which combinations
of HIV drugs work best, and have the fewest side effects. This
can help you plan a HAART combination that you can stick with.
* By regular monitoring of your T4 cell count and viral load,
you can get a better idea of how your immune system is doing
* You may be in a better position to benefit from new drugs
that are not yet available.
* You can avoid the side effects of currently available
anti-HIV drugs, which may have a bad effect on your quality of
life - in other words, the drugs may make you feel sick even
though HIV isn't making you feel sick yet.
One argument against waiting to start treatment is that HIV may
be causing ongoing immune system damage. However, it's clear
from research studies that serious illnesses are rare when a
person's T4 cell count is over 200. To be on the safe side,
most doctors would recommend HIV treatment before the T4 cell
count drops below 350 cells.
Notes on Viral Load Testing
The first time you get your viral load tested, most doctors
recommend doing two tests, about a week apart. That way, you
get a better sense of viral load levels because you have two
separate test results to compare. Viral load tests can
occasionally go wrong, and doing two tests avoids the
possibility of making treatment decision based on incorrect
Public Health Service guidelines recommend monitoring viral
load every 3-4 months if you're not yet taking HIV treatments.
Changes in viral load and T4 cell counts over time can help
work out if you're risk of disease progression is increasing.
Viral load tests aren't perfect. The test gives a rough
estimate of the amount of virus in a blood sample. Results can
change, even if you do two viral load tests on the same blood
sample. This problem is called "variability." The variability
of the viral load test can be approximately three-fold. This
means that a test result of 15,000 copies could come back
anywhere between 5,000 (three-fold less than 15,000) and 45,000
(three-fold more than 15,000). Because of this variability,
small changes in viral load test results - e.g. from 10,000 to
15,000 - don't necessarily mean that the viral load has