Epidemiology of invasive Haemophilus influenzae serotype a disease in the North American Arctic, 2006–2017

• Published in: International Journal of Circumpolar Health
• Main Authors: Tammy Zulz, Grace Huang, Karen Rudolph, Carolynn DeByle, Raymond Tsang, Shalini Desai, Stephanie Massey, Michael G Bruce
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2022
• Subjects: Haemophilus influenzae; Hia; Indigenous; Alaska; Canada; incidence; Arctic medicine. Tropical medicine; RC955-962; Arctic; Circumpolar Health; International Journal of Circumpolar Health
• Online Access: https://doi.org/10.1080/22423982.2022.2150382; https://doaj.org/article/40babc2a467c4457a786c30fecb0b116

Invasive Haemophilus influenzae type a (iHia) disease was detected in Alaska and Northern Canada in 2002 and 2000, respectively. From 2006 to 2017, 164 iHia cases (Alaska=53, Northern Canada=111) were reported. Rates of iHia disease per 100,000 persons were higher in Northern Canada compared to Alaska and were significantly higher in Indigenous (Alaska 2.8, Northern Canada 9.5) compared to non-Indigenous populations (Alaska 0.1, Northern Canada=0.4). Disease rates were highest in Indigenous children <2 years of age (Alaska 56.2, Northern Canada=144.1) and significantly higher than in non-Indigenous children <2 (Alaska 0.1, Northern Canada 0.4). The most common clinical presentation in children <5 years was meningitis of age and pneumonia in persons ≥5 years old. Most patients were hospitalised (Alaska=87%, Northern Canada=89%) and fatality was similar (Alaska=11%, Northern Canada=10%). MLST testing showed sequence types ST23 and ST576 in Northern Canada and ST576, ST23 and ST56 in Alaska. Alaska and Northern Canada have high rates of iHia disease. A vaccine is needed in these regions to protect young children.