American Journal of Public Health, Vol 90, Issue 10 1550-1554, Copyright © 2000 by American Public Health Association
Toward elimination of Haemophilus influenzae type B carriage and disease among high-risk American Indian children
EV Millar, KL O'Brien, OS Levine, S Kvamme, R Reid and M Santosham
Center for American Indian and Alaskan Native Health, Baltimore, MD 21205, USA.
OBJECTIVES: This report describes the epidemiology of Haemophilus
influenzae type b (Hib) invasive disease and oropharyngeal colonization
among Navajo and White Mountain Apache children younger than 7 years in an
era of widespread immunization. METHODS: We conducted active surveillance
for invasive H influenzae disease from 1992 to 1999 and an oropharyngeal
carriage study from 1997 to 1999. The predominant vaccine used was
PedvaxHib. RESULTS: The average annual incidence of invasive Hib disease
among children younger than 24 months was 22 cases per 100,000. Of 381
children younger than 7 years, only 1 (0.3%; 95% confidence interval =
0.0%, 1.3%) was colonized with Hib; 370 (97%) had received 2 or more doses
of Hib conjugate vaccine. CONCLUSIONS: Among Navajo and White Mountain
Apache children, Hib conjugate vaccines have led to a sustained reduction
in invasive Hib disease and a reduction in oropharyngeal Hib carriage. The
disease incidence among children younger than 24 months remains 20 times
higher than in the general US population. Hib elimination will require
additional characterization of colonization and disease in these high-risk
populations.