Update: influenza activity--United States, 1998-99 season.

In collaboration with the World Health Organization (WHO), its collaborating laboratories, and state and local health departments, CDC conducts surveillance to monitor influenza activity and to detect antigenic changes in the circulating strains of influenza viruses. This report summarizes influenza activity from October 4 through November 7, 1998; during this period, overall influenza activity in the United States was low. However, outbreaks of influenza A occurred in New York during October-November.