TABLE 1.

Distribution of the Haemophilus influenzae type b isolates included in the study

Sample groupa	No. (%) of strains in group
Vaccine failure	164 (43.5)
First period (1993-1999)	134 (35.5)
Second period (2000-2003)	30 (8.0)
Control	212 (56.5)
Children, historic control (before 1993)*	144 (38.3)
Children, contemporary control (2000-2003)**	29 (7.8)
Adult, historic control (before 1993)*	20 (5.3)
Adult, contemporary control (2000-2003)	19 (5.1)
Total	376 (100)

^a*, no vaccine available; **, vaccine available but children were not vaccinated.