Multitude of AIDS Vaccines Gives Researchers Hope for a Cure
The large number of AIDS vaccines currently undergoing clinical trials has researchers hopeful that "the sheer variety of approaches in the works will yield a winner," the Economist reports (McCarthy, Economist, 2/3). Pharmaceutical companies, NGOs and government agencies have developed a variety of AIDS vaccines, about 30 of which are currently undergoing clinical trials worldwide, according to the National Institute of Allergy and Infectious Diseases. Margaret Johnston, assistant director for AIDS vaccine research at NIAID, said, "We're nearing a defining moment in AIDS vaccine development that will be in the next five or six years. In that time period, we'll either know we're on the right track or able to more accurately predict when we might have a final answer, or we'll be very depressed and know we have to go back to the drawing board" (Christian, Chicago Tribune, 2/5). While a number of vaccines are undergoing clinical trials, only VaxGen's AIDSVAX has reached "late stage" testing. AIDSVAX aims to "prompt" the body's immune system to produce antibodies that will bind to HIV and render the virus defunct. One version of the vaccine targets the B strain of HIV, which is the type most common in the West, while other trials focus on the B and E strains -- the E strain is the form of HIV most prevalent in Asia. Trial results for the first version of the vaccine are due later this year; results from the other tests should arrive in 2002. The French-German drug firm Aventis is testing a vaccine that uses the canarypox virus, which is harmless in human beings, to carry HIV genes into humans. Preliminary results of the small-scale trials indicate that the Aventis vaccine "prompts enough of a response among killer T cells" for the company "to press forward with large-scale efficacy trials in the United States and Thailand." In addition to these two major vaccines, scientists are "tinkering" with other approaches. Some are examining "viral Trojan horses" that boost killer T cell response, some are looking at bacteria as a possible carrier for HIV and others are trying to "soup up" existing vaccine systems with other molecules known to "boost the immune system" (McCarthy, Economist, 2/3).
'Novel' Combination Vaccine
Researchers at this week's 8th Conference on Retroviruses and Opportunistic Infections in Chicago have been discussing a "novel" and "seemingly unconventional" AIDS vaccine that aims to "attack HIV with a one-two punch," the Chicago Tribune reports. This vaccine employs a "combination strategy" of two vaccines that team up to destroy the virus. The first vaccine uses antibodies to attack HIV and prevent it from infecting the host's cells. However, since the virus "may escape the antibody attack," a second vaccine is administered. The second vaccine "mimics" HIV to create cellular immunity to the virus, an immunity that is reactivated when organisms come in contact with HIV. Researchers hope that individuals' cellular immunity to HIV will be able to "sufficiently control the disease to prevent the consequences of full infection." However, scientists say that while some individuals may be "fully protected" by the virus, others may either experience a mild infection or not benefit at all as a result. Dr. Gary Nabel, head of the NIH's Vaccine Research Center, said that even if the vaccine could not protect everyone, it would help prevent transmission by shielding at least some people from contracting the virus. "Even though we might not get ... the complete eradication of the virus, we have an excellent chance to turn the tables on the epidemic," Nabel said. The combination vaccine has just begun clinical trials in the United States (Chicago Tribune, 2/5).
IAVI Sees Success for DNA Vaccine
Another major vaccine undergoing human trials is the International AIDS Vaccine Initiative's "DNA vaccine," which delivers pieces of HIV "thought necessary to stimulate a protective immunity" as naked genetic material (McCarthy, Economist, 2/3). The DNA vaccine trials, which are just getting underway in Kenya, have "broken new ground" in several ways, the Economist reports. Rather than focusing on the B strain of HIV, the DNA vaccine targets the A strain of the virus that is prevalent in Kenya. In addition, the trials are designed and conducted by local doctors, rather than Western researchers, an aspect of the trials that "helps to avoid some of the ethical issues that testing rich-world drugs on poor populations brings in its wake." IAVI also has mandated that any vaccine developed under the initiative must be priced "within the reach of poor countries," which makes any vaccine produced by the organization among "the most promising" for people in developing nations. Early trial results show "no complications," the Economist reports, but final results will take at least a year to be calculated (McCarthy, Economist, 2/3).
New Book Traces Quest for AIDS Vaccine
The new book "Shots in the Dark: The Wayward Search for an AIDS Vaccine" by journalist Jon Cohen chronicles the scientific and political landscape surrounding the quest for an AIDS vaccine and is a "must read" for anyone interested in the issue, David Perlman states in a San Francisco Chronicle book review. Cohen, who has reported on HIV/AIDS issues for the journal Science, describes how vaccine efforts first received "precious little response from the White House" and only "modest research funds." Cohen is "passionate in praise of IAVI" and critical of the "giants of the multinational pharmaceutical industry," which have displayed an "aversion to vaccine research," Perlman states. Cohen believes that while the U.S. government is "on the right track" in AIDS vaccine support, more needs to be done. He states that in addition to NIH programs, "The solution to the dilemma is to combine all of these sources into one well-funded, goal-oriented, targeted research program that exists solely to speed every potential promising lead." He proposes a "March of Dollars" that would "have its own money, in the neighborhood of $1 billion, donated by philanthropists and foundations to solve the problem." "Shots in the Dark" is "the best account of AIDS history since ... 'And the Band Played On,'" and "anyone interested in the politics and science of a global health issue" should read it, Perlman concludes (Perlman, San Francisco Chronicle, 2/4).
