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

ABSTRACT

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.

KEYWORDS:

• Haemophilus influenzae
• Hia
• Indigenous
• Alaska
• Canada
• incidence
• Arctic

Acknowledgments

We thank staff at the Vaccine Preventable Bacterial Diseases Unit of the National Microbiology Laboratory, Winnipeg, MB, Canada, and the microbiology staff at Arctic Investigations Program, Anchorage, ALASKA, USA, for technical assistance. We also acknowledge the staff at clinical laboratories in Northern Canada and Alaska for their participation in this surveillance project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Disclaimer

The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the Centers for Disease Control and Prevention.