As researchers begin the second phase of testing a vaccine against AIDS, questions are arising about what will happen once the vaccine is approved, and what will be done if things go wrong.
African and western scientists told delegates at an international AIDS conference in Nairobi that they are now ready to enter Phase Two of trials to develop and test a vaccine against AIDS.
During Phase One trials, which began two years ago, researchers said they determined that the vaccine was safe, after having tested it on about 200 volunteers in Kenya, Uganda and Britain.
Phase Two trials will involve administering the vaccine to several thousand high-risk volunteers, most likely in Kenya, Uganda, Rwanda and South Africa, to verify the vaccine's safety, and to determine the particular dosage they require. Those trials are expected to last for up to a year-and-a-half.
Phase Three will test whether the vaccine is effective and can be licensed.
At the conference, scientists from Uganda, Kenya, Tanzania, Venezuela and the United States presented details of their research. But in the ensuing question and answer session, delegates asked some tough questions.
One wanted to know the measures that researchers were taking to protect volunteers against HIV infection during the trials.
A scientist with the World Health Organization and UNAIDS Africa Vaccine Program, Dr. Jose Esparza, says the vaccine trials are following strict ethical codes set out by the Helsinki Declaration and other international norms.
"It's very practical discussions that we have had just recently in Geneva, related, for instance, to the issue of what kind of treatment should be provided to volunteers who become infected during vaccine trials," said Dr. Esparza. "WHO is ready to make a recommendation that those volunteers should receive anti-retroviral therapy for the rest of their lives."
The panelists said volunteers would not contract AIDS from the vaccine itself, but they might do so by engaging in high-risk behavior during the trials.
Other delegates were concerned that those who needed the vaccine the most would be afraid to come forward to receive it.
The president of the New York-based International AIDS Vaccine Initiative, Dr. Seth Berkley, said social scientists are looking at that issue.
"What are the attitudes of the populations," he asked. "What's going to need to happen to make them comfortable enough to use it? How do we mobilize them?"
The panelists said other issues to be worked out include distributing the vaccine, ensuring people have access to it, and convincing governments to support vaccination initiatives.