Epidemiology of Haemophilus influenzae Serotype a, North American Arctic, 2000–2005

• Other Authors: Bruce, Michael G., Deeks, Shelley L., Zulz, Tammy, Navarro, Christine, Palacios, Carolina, Case, Cheryl, Hemsley, Colleen, Hennessy, Tom, Corriveau, Andre, Larke, Bryce, Sobel, Isaac, Lovgren, Marguerite, DeByle, Carolynn, Tsang, Raymond, Parkinson, Alan J., International Circumpolar Surveillance Hia Working Group
• Language: unknown
• Subjects: Research; Haemophilus influenzae; Hia; Hib; emerging infections; indigenous; surveillance; Alaska; Canada; meningitis; pneumonia; septic arthritis; Adolescent; Adult; Age Factors; Aged; Arctic Regions; Child; Preschool; Female; Haemophilus Infections; Humans; Incidence; Infant; Inuits; Male; Middle Aged; Population Surveillance; Serotyping; Arctic; inuits
• Online Access: http://stacks.cdc.gov/view/cdc/3181/

Before the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, rates of invasive H. influenzae disease among indigenous people of the North American Arctic were among the highest in the world. Routine vaccination reduced rates to low levels; however, serotype replacement with non-type b strains may result in a reemergence of invasive disease in children. We reviewed population-based data on invasive H. influenzae in Alaska and northern Canada from 2000-2005; 138 cases were reported. Among 88 typeable isolates, 42 (48%) were H. influenzae type a (Hia); 35 (83%) occurred in indigenous peoples. Among Hia patients, median age was 1.1 years; 62% were male; 1 adult died. Common clinical manifestations included meningitis, pneumonia, and septic arthritis. Overall annual incidence was 0.9 cases per 100,000 population. Incidence among indigenous children <2 years of age in Alaska and northern Canada was 21 and 102, respectively. Serotype a is now the most common H. influenzae serotype in the North American Arctic; the highest rates are among indigenous children.