Reemergence of invasive Haemophilus influenzae type b disease in a well-vaccinated population in remote Alaska.
Before vaccination, Alaska Natives experienced very high rates of invasive Haemophilus influenzae type b (Hib) disease and carriage. Vaccination with Hib conjugate vaccine PRP-OMP (polyribosylribitol phosphate Neisseria meningitidis outer membrane protein) began in 1991 and resulted in a sharp decline in cases. In 1996, after switching to a different Hib conjugate vaccine, DTP-HbOC (which combines diphtheria-tetanus-whole cell pertussis vaccines with HbOC [Hib oligosaccharide CRM197]), cases of invasive Hib disease increased, suggesting ongoing Hib transmission despite widespread vaccination. To determine the prevalence of and risk factors for carriage, a cross-sectional study of oropharyngeal Hib carriage was conducted among Alaska Native children aged 1-5 years in remote southwestern Alaska. Of 496 children with swabs taken, 46 (9.3%) were colonized with Hib. Carriage rates varied by village from 2.2% to 13.2% and by age from 6.1% in 1-year-olds to 14.7% in 5-year-olds. Crowding was associated with Hib carriage. Widespread vaccination with PRP-OMP Hib conjugate vaccine did not eliminate carriage in this population of Alaska Natives, and ongoing carriage contributed to disease resurgence.
Galil
K
K
National Immunization Program, CDC Mailstop E61, 1600 Clifton Road, Atlanta, GA 30333, USA.
Singleton
R
R
Levine
O S
OS
Fitzgerald
M A
MA
Bulkow
L
L
Getty
M
M
Perkins
B A
BA
Parkinson
A
A
D000367:Age Factors; D000413:Alaska / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D018073:Haemophilus Vaccines / Q000009:adverse effects*; D019741:Haemophilus influenzae type b; D006801:Humans; D007198:Indians, North American; D007223:Infant; D008297:Male; D009960:Oropharynx / Q000382:microbiology; D012307:Risk Factors; D012424:Rural Population
D018073:Haemophilus Vaccines