*November 1990: Congress gives the Secretary of Health and Human Services, Louis W. Sullivan, authority to create a new list of diseases which justify exclusion from the U.S. At the time, the list includes HIV, the virus that causes AIDS, but also contains a waiver which allows travel in the U.S. for several specific reasons, including scientific conferences.

*January 1991: Sullivan presents the list, which only includes active pulmonary tuberculosis and does not include HIV, to the Justice Department. The Justice Department, which runs the Immigration and Naturalization Service, begins a review of the list.

*January to June 1991: The Justice Department is flooded with more than 40,000 pieces of correspondence on the issue, 90 percent of which call for HIV to remain on the exclusion list. In the letters, issues of drain on medical and economic resources by individuals needing treatment in the U.S. are called to the department's attention.

*June 1991: The Bush Administration creates a deadline of August 1 for a decision on the list, after which point an interim list, containing those diseases on the existing list, would go into effect. Officials at the Harvard AIDS Institute warn that without the approval of Secretary Sullivan's list, the Administration is placing the conference, scheduled for May 1992 in Boston, in jeopardy.

*August 16, 1991: Harvard announces that because of "continuing uncertainty" of the country's policy toward HIV-positive individuals, it will not hold the conference in Boston.

*September 11, 1991: Harvard announces the move to Amsterdam.