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AIDS in Africa: vaccine trials

Susman, Ed

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AIDS in Africa

Although the statistics are numbing, the real effect of AIDS in Africa rests in how the disease has ripped the infrastructure of the continent apart, especially in the sub-Saharan nations where prevalence rate of HIV infection remains in double digits in 16 countries. But Dr. Thomas Quinn, MD, professor of medicine at Johns Hopkins University, Baltimore, Maryland, USA, described specifically what happens when a disease kills 17 million people on one continent in two decades. Dr. Quinn told the American Society of Tropical Medicine and Hygiene in Denver, Colorado, that in several countries, half of all illnesses are now related to AIDS, resulting in a reduction of the gross workforce. One has to consider Africa's main agricultural society – seven million farmers have died due to AIDS – and also the educational process—85% of teacher deaths in the last 20 years have been due to AIDS. AIDS is the leading cause of death within the continent. Because it affects many people in their young, reproductive ages and because of the loss of life among those young individuals who are parents, we are left with a very large number of orphans who are not necessarily infected with HIV. He said that even those who have escaped the infection that has claimed their parents do not escape an early death, as it has been shown that HIV-uninfected children born to HIV-infected mothers have decreased survival compared to children who are born to non-infected individuals. He also suggesting that becoming an orphan in Africa — home to more than 85 of the world`s AIDS-caused orphans — is a health hazard by itself.

Dr. Quinn said that from the global perspective, the HIV epidemic has reversed many of the developmental gains that have been made in many areas of the world; in particular it has reversed those gains made over the last three decades. There has been an economic decline, particularly on the continent of Africa with estimates of that decline ranging from 10 to 40 – a staggering figure in an area that is already economically fragile. It has resulted in health system chaos where in some places 50–80 of hospital beds may be occupied by HIV-infected people with increasing opportunistic infections many of which go untreated. All of this results in a spiraling factor of political instability. This is the area of the world where AIDS has entrenched itself in the last two to three decades, and is still spiraling out of control. The spread of HIV continues unrelentlessly across the continent with perhaps the south seeing the greatest rate of increase. AIDS is responsible for one in five fatalities in the continent of Africa, but Dr Quinn believes that with access to treatment this should be reversed.

Vaccine trials begin

A key to overcoming AIDS throughout the world is the need for a vaccine against the virus, and steps in that direction were announced recently by the US National Institute of Allergy and Infectious Diseases. The NIAID began clinical tests of a novel vaccine that targets the three most globally important HIV clades. Developed by scientists at the NIAID's Dale and Betty Bumpers Vaccine Research Center, the vaccine incorporates HIV genetic material from clades A, B and C, which cause about 90 of all HIV infections around the world. ‘‘This is the first multigene, multiclade HIV vaccine to enter human trials,’’ said NIAID Director Anthony S. Fauci, MD ‘‘It marks an important milestone in our search for a single vaccine that targets U.S. subtypes of HIV as well as clades causing the global epidemic.’’ The DNA vaccine incorporates parts of four HIV genes. Three of these vaccine components are modified versions of the HIV genes gag, pol and nef taken from clade B, the subtype that predominates in Europe and North America. The fourth vaccine component is derived from the HIV gene env from clades A and C which are found extensively in Africa. ‘‘This trial begins a process that we hope will culminate in a globally effective HIV vaccine,’’ said Gary Nabel, MD, who heads the vaccine research center. ‘‘The first step is to develop a multiclade vaccine. If our candidate elicits an effective immune response and proves safe in clinical testing, we will include additional components in subsequent trials in hopes of boosting this response. Ultimately, we aim to build a potent vaccine designed to prevent HIV infection.’'

The first phase of the trial, which is being conducted at the National Institutes of Health in Bethesda, Maryland, will test the vaccine's safety and will enroll 50 healthy, HIV-negative volunteers who will be given either the vaccine or placebo in a dose escalation trial that will continue for a year.

© 2003 Lippincott Williams & Wilkins, Inc.