Prevention is the only real hope in fighting AIDS, speakers said yesterday at a symposium held in the Science Center.

The symposium, sponsored by the Harvard-Radcliffe Future Physicians Society, was designed to provide information to pre-med students, other undergraduates and the Boston and Cambridge communities about the future effects of AIDS, said Holly S. Gilmer '88, president of the society.

Dr. David Baltimore, an affiliate of the Whitehead Institute at the Massachusetts Institute of Technology (MIT) and co-chairman of the Institute ofMedicine commission on AIDS, discussed both theshort and long term effects of the AIDS virus onsociety.

"Predictions say that by 1991 a quarter of amillion people who are currently infected willhave gotten AIDS," he said. "That is a big numberwhen it is looked at from the point of view of thenumber of years of potentially productive lifelost."

In the long run, Baltimore said, the majorchallenge to the medical community is to find avaccine for the virus and to find drugs to treatthe illness.

He said the discovery of the drug AZT--orazidothymide--was an important step forward fortreatment, because it has generally been verydifficult to find drugs to treat viruses. "Wecan't expect that AZT will be followed by betterdrugs." he said. "It is very frustrating,especially for those suffering."

Although vaccines are usually easier todevelop, Baltimore said there are still no reportsof any AIDS vaccines that work on animals and theonly trials of proteins that "may or may not findan antibody response."

AIDS is a particularly difficult disease todevelop a vaccine for because most vaccines workby mimicking a virus--thus stimulating the body toproduce antibodies--and the body does not produceantibodies to AIDS, Baltimore said.

Because even optimists in the medical andscientific communities are saying that a vaccinecannot be found for at least five years, "the onlyway to prevent infection is through education,"Baltimore said. "Our only hope is to keep thepeople who are uninfected, uninfected."

"Very few people in the world are suicidal andif we can convince them that they are killingthemselves, they will change their behavior."Balti more said.

The other speaker at the symposium was Dr.Howard Hiatt, the former dean of Harvard's Schoolof Public Health, who is currently professor ofmedicine at Brigham and Women's Hospital.

Hiatt discussed the impacts of the disease."The absence of a vaccine and therapeutie agentsleave grim prospects for biology and medicine." hesaid. "With no mechanisms to change the prospectsin the near, or perhaps even distant future, ouronly hopes are to encourage serious, enlightenedresearch, and to focus on prevention."

With the use of education, the gay communityhas been able to change its sexual behavior andslow the transmission of the disease, Hiatt said.By contrast, there has been no success amongintravenous drug users, partly because the waitingtime for addicts who want to join a rehabilitationprogram is almost a year. "For up to a year, thedrug users are either disseminating the virus orat risk for getting it," Hiatt said.

Other impacts of the AIDS virus include theincredible costs of the treatment. It is estimatedthat by 1991, the costs to insurance companieswill be in excess of $10 billion.

The virus is also presenting serious ethicalissues, as some doctors question theirresponsibility in the care of AIDS patients andothers demand to know whether their patients havebeen infected with the virus, Hiatt said."Although only 10 health workers have gotten AIDSfrom their patients, the number will grow," hesaid.

Confidentiality is also a problem, and medicalprofessionals are facing many questions to which"there are no rules. All of this is evolving,"Hiatt said. "Doctors are confronted with theconflict between the responsibility of being adoctor for one patient and for society as a whole.

Addressing the pre-meds in the audience, Hiattsaid that students who turn away from the medicalprofession because of the threat of AIDS, "dosociety and themselves a bad turn.