Influenza activity--United States, 2000-01 season

This report summarizes influenza activity in the United States during November 26, 2000-January 13, 2001. Influenza activity was low to moderate but increasing in the United States. Since October 1, the most frequently isolated viruses were influenza A (H1N1) and were well matched antigenically with the 2000-01 influenza A (H1N1) vaccine strain.