Decline of pediatric admissions with Haemophilus influenzae type b in New York State, 1982 through 1993: relation to immunizations.

Objectives: To evaluate the impact of vaccination for Haemophilus influenzae type b (Hib) on pediatric hospital admissions in New York State, and to identify risk factors in children who continue to be admitted for Hib invasive disease.

Methods: Retrospective review of hospitalizations in New York state from 1982 through 1993 and a survey of immunization records from physician offices in Monroe Country, New York.

Results: In 1982, 769 children were admitted to New York state hospitals for Hib-related conditions; by 1993, this had decreased to 133. Significant declines during the study period occurred in the age-adjusted admission rates for Hib meningitis, septicemia, pneumonia, and epiglottitis, but not for arthritis and osteomyelitis. In 1993 alone, 712 admissions, 18 deaths, and 135 episodes of morbidity were avoided. Since 1991, the rates of admissions for Hib-related conditions have remained fairly constant. Minority subjects continue to be twice as likely as white subjects to be admitted for invasive Hib disease (0.44 vs 0.17/100,000). Children living in urban Rochester also are more likely to be admitted and less likely to be completely immunized against Hib (61%) than those living in suburban areas (82%).

Conclusions: Although Hib vaccine has had a major impact on hospital admissions for Hib-related conditions, the goal of completely eliminating Hib disease will require programs targeted at groups at high risk, such as minorities and those living in cities.