Haemophilus influenzae type B invasive disease in urban and rural children: immunization patterns and prevalence of disease

Increase in invasive pneumococcal disease in children associated with shortage of heptavalent pneumococcal conjugate vaccine

The authors investigated the impact of heptavalent pneumococcal conjugate vaccine (PCV7) shortage on the rate of invasive pneumococcal disease (IPD). Vaccination status and number of doses delivered was determined. Regression analysis using an exponential decay model was used to predict the expected rate of IPD in the shortage period if IPD continued to decline at the same rate as in the availability period. The rate of IPD decreased from 15.5 to 6.5 with vaccine availability (P < .00001) and increased to 7.2 with shortage (P = .69). Based on the model, IPD rate would have been 3.6 if the decrease continued at the same rate when there was no shortage; this was statistically significant (95% prediction interval, 2.7-4.1). The rate of IPD correlated directly with the number of PCV7 doses delivered, r = -.98. Continuous availability of the PCV7 would have resulted in a statistically significant lower IPD rate compared to the measured IPD rate in the vaccine shortage period.

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.