Resurgence of pertussis--United States, 1993.

From January 3 through December 4, 1993 (weeks 1-48), 5457 pertussis cases were reported to CDC--an 82% increase over the number reported during the same period in 1992 (3004) and the highest annual number of cases reported since 1967 (Figure 1). Compared with 1992, the number of reported pertussis cases increased in 35 states, especially those in the New England, middle-Atlantic, North Central, and Mountain regions (Figure 2). During 1993, large outbreaks have occurred in Chicago and Cincinnati. This report summarizes epidemiologic characteristics of pertussis cases reported through December 4, 1993.