The National Academy of Sciences' Institute of Medicine holds an 11 a.m. briefing on a report, "Vaccine Supply and Innovation," at the academy, 2100 C St. NW. The American Defense Institute sponsors a seminar on Central America beginning at 9:30 a.m. in the auditorium of the Dirksen Senate Office Building. TUESDAY

William C. von Raab, commissioner of the U.S. Customs Service, and Gunter Eser, director general of the International Air Transport Association, hold an 11 a.m. news conference to discuss the IATA's adoption of Customs' guidelines for deterring drug smuggling on commercial aircraft. The briefing will be held at the Customs Service Building at 1301 Constitution Ave. NW. WEDNESDAY

Interior Secretary Donald P. Hodel holds a briefing before embarking on a month-long trip to inspect departmental operations and facilities in the West. The session will be at 9:30 a.m. in Room 5160 of the Interior Building. THURSDAY

The Fund for an American Renaissance and the National Center for Neighborhood Enterprise sponsor an urban affairs conference at the Mayflower Hotel. The conference, "Revitalizing Our Cities: Jobs, Housing, Entrepreneurship, Economic Growth," will begin at 9 a.m. People for the American Way holds a news conference on its campaign against the expected nomination of Herbert Ellingwood as assistant attorney general for legal policy. The briefing will be at 10:30 a.m. at the Capital Hilton Hotel. FRIDAY The Bureau of Labor Statistics releases the July unemployment figures. The Full Employment Action Council holds a briefing on its report, "Unemployment in America: Real Numbers, Real People," at 11 a.m. in Room 2257 of the Rayburn House Office Building.