Figure 1.
Annual incidence of pertussis in Korea and list of tested strains in this study. Data of annual incidences in Korea were retrieved from the WHO data and disease web statistics system of KCDC. The upper line and number indicate annual pertussis incidence of Korea from 2000. No isolate tested in this study is shown in the lower table. Old isolates are defined as strains isolated before 1999, as indicated. The strain number of the isolates before 1980 was assigned as K00 and the strains named as KNT00 were the isolates after 1990.