The Life and Times of HIV
New Infections Continue While Super Strains of HIV Grow
The Guest That Wouldn't Leave
Just how much do you know about the life of this small virus that lives inside your body? I have a friend who looks at HIV as a long-term unwelcome in-law who has come to visit and just won't leave. The only problem, of course, is that this guest is slowly and methodically destroying the house-ripping out the drywall, exposing the studs, and cutting into them so that eventually the house will fall. Gloomy analogy, but what does HIV really do to the body, if left alone, untouched by drugs in the body?
A recent study of 270 people examined just this. The first finding of the study was that in the first 3 years, the viral load in the blood of most of these participants remained stable. The virus just moved in looked around but didn't go crazy and start reproducing like mad. However, it did slowly start to eat away at the immune system, killing off an average of 100 CD4 cells each year.
Of course, things are never quite that simple. People with higher viral loads ended up losing CD4 cells much more quickly, thus making viral load a strong predictor of how quickly someone will progress to AIDS. One way to look at this is the example used at the 11th World AIDS Conference: AIDS is like a train wreck waiting to happen. Imagine a train on a track heading for a cliff. The train is HIV infection, the viral load is the speed of the train, and the CD4 count is the distance to the site of the accident -- another gloomy analogy.
HIV: A Discriminating Virus
Viral load is a very important factor and predictor of health, but viral load, as well as CD4 counts, seem to be age-, race- and gender-dependent. Recent studies now show that viral load in women is much less than in men. This can have a major impact on how we view the success or failure of a therapy and predicting when to switch drugs. One study showed that on average women have about 20 percent less virus in the blood than men. This same study also showed that women, on average, have fewer CD4 cells than men.
Race also came into play when looking at viral load. People of color had viral loads about 32 percent lower than Caucasians. And older people had higher viral loads than their younger counterparts. So, depending on the age, gender, and race of the "host," the HIV virus can act and reproduce very differently.
If a man and a woman had the same 10,000 viral load, the woman would, according to this study, be more likely to progress to AIDS than the man. That is, she would have a risk of progression similar to a man with a viral load of 20,000 twice as high, or 20,000.
New HIV Infections: It Just Keeps Going and Going
Session 65 at the 6th Conference on Retroviruses and Opportunistic Infections (CROI) looked at HAART and asked the question: Is the therapy having an effect on the number of new HIV infections occurring? The sad but true answer, according to Jonathan Kaplan of the Centers for Disease Control in Atlanta, is No.
A model has been developed, that, although it has some definite flaws, explains why new infections continue at a steady rate. The model says that of the 750,000 people with HIV in the United States, 560,000 were infected sexually. (The flaw here is that the IV drug users that make up the difference are also having sex, something the researcher has left out). Of these 560,000 only half are actually getting care. The presenter believed that the other 280,000 people either don't know they are infected, or know but cannot, or do not, access services. These people continue to spread HIV at higher rates than those in care.
The theory is that those getting care are causing some new infections, but not as many, because they have lower viral loads and probably have been educated about safe sex practices. The conclusion is that testing, counseling, and early access to treatment for all people with HIV is the only way to slow new infections.
There are several other studies showing that new infections are continuing to occur at steady rates. One of these was conducted in San Francisco between 1996 and 1998. From January of 1996 to January of 1998 there was no significant change in the number of new infections that occurred in that city. This study is consistent with national numbers showing that new infections are occurring in a steady and continuous way with no significant decline in the past few years.
Super Strains -- Resistant Virus is Spreading
A few studies at this year's CROI focused on the increasing problem of spreading of resistant HIV. Some people who are just testing positive to the virus are already resistant to some drugs and in some cases to one or more classes of drugs, leaving them with few if any drug options.
One study conducted by a Veterans Administration hospital examined 114 newly infected people from major metropolitan areas across the United States. The study found that overall, 21 percent of those studied had some type of resistance to one or more of the three major classes of drugs.
As drug resistant viruses continue to spread, it is very important for those who test positive to get a genotypic or phenotypic test done prior to starting therapy to see if there is any drug resistance. These are new tests, often expensive, and complicated to interpret. Some insurance may cover these tests, but others won't. It is best to work closely with your provider and have them speak or write to the insurance company to explain why the test is needed and important. Get a good, experienced, health care provider to run and interpret these tests for you, or they will not be worth your time or money.
This article was provided by Seattle Treatment Education Project. It is a part of the publication STEP Perspective.