HIV / AIDS Update July 25 from the 3rd International AIDS Society Conference
HIV / AIDS Conference - July 25, 2005 Highlights #1
Dr. Eric Daar presents highlights and daily summaries from the 3rd International AIDS Society Conference on HIV Pathogenesis and Treatment in Rio de Janeiro, Brazil. (held July 24-27 2005)
HIV / AIDS Conference - Monday July 25, 2005
Welcome from the 3rd International AIDS Society Conference on HIV Pathogenesis and Treatment in Rio de Janeiro Brazil. The International AIDS Society (IAS) is the world's professional society for scientists, health care and public health worker, and other engaged in HIV/AIDS prevention, control and care. Delegates arrived in Rio de Janeiro from across the globe to share information regarding a wide range of scientific areas. This meeting includes new information regarding novel therapeutic agents as well as prevention measures in both the developed and developing world. Recent International meetings have further focused on the roll out of antiretroviral therapy to some of the countries most devastated by the HIV/AIDS epidemic.
The first full day of the meeting began with a presentation by Dr. Francine McCutchan who leads the Global Molecular Epidemiology Programme for the U.S. Military HIV Research Program. Dr. McCutchan presented data from work showing the diversity of HIV strains around the world. In addition to outlining how such extensive viral diversity may hinder the ability to develop a protective vaccine she also showed how these viruses can further mix within a given individual. This situation has been referred to as recombination and it rapidly results in new strains that are different from those previously recognized. Many of these new viruses have subsequently spread throughout different parts of the world. More recent work has used novel laboratory techniques to explore how often a given individual is infected by more than one strain of HIV, so called co-infection. This can occur as a result of an uninfected person being simultaneously infected by two different partners around the same time, or for a chronically infected person to be re-infected by a new partner, so called superinfection. This study showed that amongst those chronically infected who have many partners there is an increasing number with evidence of superinfection, in fact it may occur in up to 40% of select individuals. These types of studies have major implications for those infected by HIV. Firstly it illustrates how variable HIV can be, which will certainly make vaccine development very challenging. In addition it supports current recommendations that those infected with HIV do everything possible to prevent themselves from becoming superinfected. In fact, other studies have suggested that when superinfection occurs it is often associated with disease progression.
A second plenary talk in the morning was by Christopher Beyrer, Associate Professor of Epidemiology and International Health at the Johns Hopkins Bloomberg School of Public Health in Baltimore Maryland. Dr. Beyrer does research around the world and spoke of the growing epidemics of HIV, particularly in Eastern Europe. In this region of the world many new infections result from intravenous drug use. He further explained that many countries have failed to deal with the unique problems of intravenous drug users. For example, in the roll out of antiretroviral therapy to poor countries distribution has often not provided for those who use drugs. In addition, many areas do not promote risk reduction in this group, such as by distribution of clean needles, a method that has been proven in several studies to reduce HIV transmission among drug users.
There were several other presentations during the day that will be of interest to the community. Dr. Blick presented a paper called "Patient zero: The Connecticut source of the multi-drug resistant dual-tropic, rapidly progressing HIV-1 strain found in New York City." He first reminded the group of a unique case that was reported by a press release earlier this year from the New York Health Department. It was a crystal methamphetamine-using individual who appeared to have been infected for months to a few years that had acquired a virus resistant to most antiretroviral agents and was experiencing rapid disease progression. The primary provider for this patient was contacted by companies that performed the resistance testing stating that they identified an individual with a virus that appeared to be highly related to that of the patient. Dr. Blick described how the person identified by the company, along with this individual's stable HIV-infected partner admitted to sexual relations with the "NY patient" around the time of his new infection. Further studies demonstrated evidence that there was some exchange of viruses between the HIV-infected stable partners and that their viruses were very similar to that of the New York patient. Despite this, the persons that were presumed to be the source or the virus had been infected for many years and did not experience rapid disease progression, as seen in the NY case. While there are still many details that need to be sorted out from these cases, there are several important lessons to be learned. First, it illustrates that crystal methamphetamine-use continues to be an important driving force behind the HIV epidemic. Second, it emphasizes the importance of using barrier protection, including among HIV-infected partners, where in this case there was evidence of possible superinfection which could have adverse effects on the course of disease. Finally it shows that rapid progression is influenced by a multitude of factors, not just the virus. Further research related to patients like this may someday advance our understanding of why different people handle viruses differently.
Another presentation emphasized concerns related to increasing transmission of drug resistant virus. In this case the group from the University of North Carolina studied over 200 patients followed in a cohort. They found that 170 were taking antiretroviral therapy when interviewed about behaviors, with 60% not adhering closely with their treatment regimen. Moreover, just under half had detectable viral load at the time they were surveyed. When questioned about sexual activity it was found that approximately 50% had unprotected sex in the previous year and this was the case with increasing frequency in those who admitted to poor adherence with their medical regimen. Moreover, drug resistant virus was commonly among those with drug resistant virus. Together this data suggests that the risk of transmission of resistant virus may be high among select groups of HIV-infected individuals.
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