Stopping the spread of AIDS is possible, but will happen only when people exercize more caution in their social behavior, the director of one of the nation's leading health research centers said yesterday at a Harvard health conference.

"The question is not can it be [stopped], but will it be and when," said James O. Mason, Director of the U.S. Public Health Service Centers for Disease Control, Mason said that interrupting transmission "is the only tool we have to combat this disease."

New York City Commissioner of Health David J. Sencer and SPH Chairman of Cancer Biology Myron E. Essex joined Mason in addressing an audience of 350 at the School of Public Health's Health Policy Forum, the largest turnout the Forum has ever attracted.

All three panel members cited the dangers of AIDS--acquired immune deficiency syndrome--and prescribed precautionary measures to avoid the deadly disease.

In the past five years, over 13,000 Americans have contracted AIDS, moderator and SPH Dean Harvey V. Fineberg '67 said. None have recovered and half have died.

Public health officials say the virus infects at least another million Americans, five to 20 percent of whom will develop AIDS within five years. The disease is most prevalent among male homosexuals, intravenous drug users and hemophiliacs.

"AIDS has spawned a second epidemic, one of fear," remarked Fineberg in his introductory remarks.

"The disease is not transferred by coughing, sneezing, doorknobs or toilet seats," Mason said.

Mason urged members of the audience to communicate a message of caution to the public. His suggestions included abstinence from sexual intercourse with AIDS patients or members of "high risk groups," and the use of condoms, even though no clinical studies have proven that they prevent the transmission of the disease and to avoid using intravenous drugs.

"The kind of people who are at risk are the college co-ed and her boyfriend," Fineberg said.

"This message," said Mason, "is a sort of soft cloud because it depends upon the behavior of many. It asks some sacrifice." He ended his remarks with a plea for society "to act diligently and rapidly to end this epidemic.