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Washington (AFP) July 14, 2010 After decades of trying to develop a vaccine against AIDS, global health authorities are finally beginning to make "significant advances" towards their goal, Anthony Fauci, head of the US institute of infectious diseases, told AFP. "Up to a few years ago, even though we have been trying for a couple of decades to develop a vaccine, unsuccessfully, we have not even had a small clue that we were going in the right direction," Fauci told AFP. But two key events that have taken place in the past few years have changed that and led to "significant advances in the development of a vaccine," said Fauci, who is head of the National Institute for Allergy and Infectious Disease (NIAID). The first of those key turning-point events was a clinical trial of an HIV/AIDS vaccine which was conducted last year in Thailand on 16,000 people. "The results showed a small to modest positive effect on the acquisition of HIV -- not good enough to be able to distribute a vaccine but good enough to tell us that it was a conceptual advance that at least makes us feel now that a vaccine is possible," Fauci said. Then, last week, scientists at NIAID published a paper in the journal Science about research that had helped them to identify two antibodies in an HIV-positive individual, which, when put together "block 90 percent" of HIV strains, Fauci said. "What that is telling us is that you can identify the portion of the virus that you would like to use as a vaccine, because we know that when the antibodies bind to that portion, it knock down the virus," he said. The next step will be to try to inject that part of the virus into an individual to produce a protective response against HIV infection, said Fauci in an interview with AFP days before the 18th international conference on AIDS, to be held in Vienna, Austria. The Thai study and the report in Science have left scientists feeling "much more confident that ultimately we will have a vaccine" against HIV/AIDS, although it was still impossible to say exactly when that would be, said Fauci. An AIDS vaccine was probably several years away, which means that in the meantime, the fight against HIV/AIDS must continue to focus on prevention and use tried and true tactics such as condom distribution, male circumcision, blocking mother-to-baby transmission and offering syringe exchange programs, he said. Ways have to be found, too, to improve access to these preventive measures, especially in developing countries where only 20 percent of "populations who would benefit" actually have access to them, he added. Along with improving access to the preventive methods, Fauci urged global health authorities and governments to continue to work to develop other forms of prevention, such as microbicides. And he recommended "treating as many people as we possibly can because we know that when you treat more people, you lessen the probability that they would infect other people. "You could almost have what we call treatment as a form of prevention," until a vaccine is finally developed, said Fauci.
HIV/AIDS: Factfile WHAT IS AIDS? Acquired Immune Deficiency Syndrome, which first came to light in 1981, is the term for a progressive weakening of the immune system. The body is exposed to pneumonia, tuberculosis, fungal disease and other opportunistic infections, as well as specific types of cancer, that ultimately are fatal. WHAT CAUSES IT? The cause of AIDS is the human immunodeficiency virus (HIV), a retrovirus suspected to have leapt the species barrier from animal primates in central Africa. HIV is found in blood, semen, vaginal secretions and breast milk. It enters the body through cuts or sores or by directly infecting cells in the mucous membranes in the genitals or anus. The main modes of infection are unprotected sexual intercourse, shared use of drug syringes, from a mother to her unborn child and transfusion of contaminated blood. HOW DOES HIV WORK? HIV destroys key white-blood cells called T-helper lymphocytes. It does this by latching onto a molecule known as CD4 on the cell's surface. The virus then penetrates the cell, hijacking its enzyme-making machinery in order to replicate itself. Baby viruses then burst out to infect other T cells. HOW LONG DOES IT TAKE? The time from initial infection to full-blown AIDS in untreated patients is about nine years, but the time can vary according to the individual. From AIDS to death generally takes between six months and three years. WHAT IS THE TOLL? At least 25 million people have been killed by AIDS since the disease came to light in 1981. According to the UN agency UNAIDS, at the end of 2008, around 33.4 million people were living with HIV, 22.4 million of them in sub-Saharan Africa. In 2008, 2.7 million people became infected, a 30-percent fall compared with the peak of HIV's spread 12 years earlier. IS THERE A CURE? There is currently no cure for HIV, but there is a treatment that can suppress the virus to very low levels. Antiretroviral drugs, a combination of two or three medications that inhibit viral reproduction or stop the virus from fusing with the CD4 T cell, are a lifesaver for millions. But they can also have powerful side effects, including diarrhoea, nausea and cramps, and carry a risk of treatment failure. There are more than 20 antiretroviral drugs today. In poorer countries, 9.5 million people are in immediate need of the therapy, but only four million have access to it. HOW CAN HIV BE PREVENTED? For sexual intercourse, a latex barrier (a male or female condom) is highly effective. Trials in Africa have shown that male circumcision, which removes mucous cells from the foreskin, can roughly halve the risk of infection for the man, although there is no protection for an uninfected woman. Mother-to-child transmission can be combatted by treating the mother-to-be and the newborn with antiretrovirals. Contamination by blood transfusion is now rare in most countries, thanks to screening of blood donations. Needle exchange programmes, in which a used syringe is swapped for a clean one, can help reduce transmission among drug addicts. WHAT ABOUT A VACCINE? The search for an HIV vaccine is arguably the toughest challenge of all. Trials of prototype vaccines have shown negligible protection or none at all. However, some encouraging work has been achieved in the lab in identifying antibodies -- natural frontline troops in the immune system -- that could hopefully be primed to recognise the virus. The effort for an HIV-preventing microbicide gel, which could be used in anal or vaginal intercourse, has a similar report card. SOURCES: UNAIDS; www.avert.org; US National Institutes of Health (NIH); World Health Organisation (WHO); International AIDS Vaccine Initiative (IAVI).
HIV/AIDS in figures Figures are for the end of 2008. An update is expected later this year. 1) TOTAL INFECTIONS IN 2008: WORLD: Around 33.4 million people living with HIV, in a range of 31.1 million to 35.8 million. BY REGION: Sub-Saharan Africa: 22.4 million South and Southeast Asia: 3.8 million East Asia: 850,000 Latin America: 2.0 million North America: 1.4 million Western and Central Europe: 850,000 Eastern Europe and Central Asia: 1.5 million Caribbean: 240,000 Middle East and North Africa: 310,000 Oceania: 59,000 2) NEW INFECTIONS IN 2008: WORLD: 2.7 million people became infected in 2008, unchanged from 2007. BY REGION: Sub-Saharan Africa: 1.9 million South and Southeast Asia: 280,000 East Asia: 75,000 Latin America: 170,000 North America: 55,000 Western and Central Europe: 30,000 Eastern Europe and Central Asia: 110,000 Caribbean: 20,000 Middle East and North Africa: 35,000 Oceania: 3,900 3) AIDS DEATHS IN 2008: WORLD: Around two million people died from AIDS-related causes in 2008, unchanged from 2007. BY REGION: Sub-Saharan Africa: 1.4 million South and Southeast Asia: 270,000 East Asia: 59,000 Latin America: 77,000 North America: 25,000 Western and Central Europe: 13,000 Eastern Europe and Central Asia: 87,000 Caribbean: 12,000 Middle East and North Africa: 20,000 Oceania: 2,000 Source: 2009 AIDS Epidemic Update
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