hiv viral load - TheBody.com's Bulletin Boards

and Perhaps a Lifesaver?

By Paul Galatowitsch, Antonio Urbina and Timothy Law Snyder

Paul Galatowitsch is a health care consultant. Antonio Urbina is the director of clinical HIV and AIDS education at St. Vincent's Hospital. Timothy Law Snyder is a professor of mathematics and computer science at Fairfield University.

In the summer of 2003, a young man went to his doctor complaining of a high fever, headache, painful joints and muscles and a rash. His doctor diagnosed the flu, and told him to rest and drink plenty of fluids. After a week, the man's symptoms went away.

Unknown to this young patient and his doctor, however, those symptoms were caused by a very recent infection of HIV, the virus that causes AIDS.

An HIV testing technology that has been around for more than a decade can diagnose recent infections like this man's. Unfortunately, the technology is rarely used in New York City.

In this patient's case, his partner had infected him two weeks earlier, and his body was responding to the unchecked replication of HIV. Although 10 to 40 percent will not experience these flu-like symptons, every person who becomes infected with HIV goes through acute HIV infection. This phase of infection presents an enormous risk both to the person who has become infected and to his sexual partners.

Here's why: during the peak stage of early HIV infection, the amount of the virus circulating in the newly infected person can make him up to 1,000 times more likely to transmit HIV than during the chronic stage of the infection, which is typically eight years or more after infection and before the onset of AIDS. Had the young man's condition been properly diagnosed, he could have been told that any sexual activity during this initial phase of infection would be alarmingly dangerous to others.

Surprisingly, such misdiagnosis is routine. Despite the availability of a reliable method to detect this initial phase of infection, the polymerase chain reaction viral load test, medical providers worldwide will diagnose only about one of every 60,000 cases of acute HIV infection. And this is a considerable problem in reducing the spread of HIV

The viral load test detects HIV itself, unlike the more standard HIV test, which detects only the antibodies that develop weeks or more rarely months after infection. Indeed, most people will get negative results on an antibody test for three to six weeks after infection.

The viral load test, however, can detect HIV five to seven days after infection, and since the first few weeks correspond to the period of highest infectivity, detection then is the most useful in stopping the spread of the disease. Unfortunately, commercial viral load tests are expensive, at $200 to $300 each. As a result, health care providers avoid using them, and instead rely on the antibody test, which costs about $5 [Physicians periodically do order HIV RNA testing for their HIV patients, but only for those who are chronically infected, to monitor their viral loads as a means of evaluating the effectiveness of therapy or to help determine the appropriate time to initiate or change treatment--Ed]

But North Carolina has discovered a way to get around the high cost. Since 2002, the state has submitted the blood of every person testing negative for antibodies at its sexually transmitted infection clinics to viral load testing through a blood pooling system. In a May 2005 issue of the New England Journal of Medicine, Christopher Pilcher and his colleagues, who run the North Carolina viral load testing program, explain that all HIV negative blood samples are pooled into batches of 90 and tested. If a batch tests positive, it is examined sample by sample until the positive specimens are found.

By pooling tests, North Carolina has reduced the cost of a combined HIV antibody and viral load test to $3.63, from $90, the noncommercial state's cost. In 2004, North Carolina's pooled testing program identified an additional 6 percent of HIV cases at its clinics. San Francisco established the same testing program in 2003, and has identified 10 percent more HIV infections.

By our conservative calculations, if New York City submitted the approximately 38,000 HIV tests it conducts annually to a combined viral load and HIV antibody testing program; it would identify 24 to 36 cases of acute HIV infection and avert 6 to 72 HIV transmissions each year. Multiplying those figures by $300,000, the lifetime cost of treating a person with HIV, shows that pooled viral load testing would save the city $1.8 million to $21.6 million each year.

Unfortunately, New York City's Department of Health has refused to use this procedure at its sexually transmitted infection clinics. Instead, by January 2005, the department had shifted all of its resources to rapid HIV antibody testing, a procedure that provides results in one hour but cannot determine acute HIV infection. The decision not to combine rapid HIV antibody and viral load testing will incur needless tragedies for many New Yorkers and cost the city millions of dollars in additional health care expenses.

07/20/05

Source

Post Extras: Remind Me!