CNN HEALTH Special Section

Testing the AIDS vaccine will be ethically challenging for researchers

(CNN) -- This summer, San Francisco-based researchers launch the first global AIDS vaccine trials -- a medical step forward which is nonetheless rich in moral dilemmas. It's one of the most promising developments in the war on AIDS, and one of the most ethically challenging, as researchers seek uninfected but vulnerable participants.

Vaxgen Inc. has devised a three-year study in which participants will be counseled around 15 times.

"In the U.S., it'll be over 5,000 men who have sex with men and women who have sex partners who are HIV positive," says Vaxgen's Dan Reiner.

One out of every three will get a placebo. In trials among 2,500 needle users in Thailand, placebo and vaccine will be divided evenly.

Trials of this nature raise the risk of false security among participants, according to Dr. Lawrence Gostin, a professor of law and public health at Georgetown University.

"The ethical thing to do is to tell both the placebo controlled group and the experimental group that they should avoid having unprotected sex. They should avoid sharing needles when they use drugs," Gostin says.

As part of the study, each time participants receive counseling they will be reminded that they could be getting a placebo and cautioned against needle-sharing and unprotected sex.

No risk of AIDS infection from vaccine

The vaccine itself poses no risk of infecting participants, but there are other moral and social challenges facing trial participants- issues of privacy and confidentiality.

"If you're participating in an HIV vaccine trial, in itself, you've got a privacy problem, people will assume you to be at risk," says Dr. Gostin. "They might think you're a homosexual or a user of drugs."

Another area of concern for participants is discrimination. If the vaccine makes a person test positive for AIDS, even though they don't have the virus, they could face discrimination in areas ranging from jobs to health insurance.

Researchers are also taking steps to ensure that participants from third world countries will have access to any vaccine that is approved.

"We've already been talking with the World Health Organization, U.S. banks, the World Bank and other organizations like U.N. AIDS to work with them when the vaccine is proven effective, to be able to get it to them."

Vaccine trials in the United States will take place in Chicago, Denver, Los Angeles, Philadelphia and St. Louis.