Alberta health authorities have raised concerns about the presence of a rare bacterium called Haemophilus influenzae type b (Hib) among individuals experiencing homelessness in Calgary. A communication sent to emergency departments and urgent care providers by Primary and Preventative Health Services, as reported by CBC News, highlights a “cluster of invasive Hib cases linked to a distinct genetic sequence type.”
The memo indicates that this particular strain, previously identified in British Columbia, has now emerged in the Calgary area within the homeless and housing unstable adult population. In 2022, Vancouver Island experienced an outbreak of Hib among homeless and drug-using individuals, resulting in fatalities. Alberta’s health department reported eight cases of Hib in the Calgary zone in 2025, compared to three cases in 2024 and two cases between 2019 and 2023.
Dr. Isaac Bogoch, an infectious disease specialist at Toronto General Hospital, mentioned that Hib used to primarily affect children until a vaccine was introduced as part of routine childhood immunizations. While Hib infections are not common, healthcare professionals occasionally encounter them. Dr. Bogoch emphasized the importance of recognizing the potential risk of Hib in patients with backgrounds such as homelessness.
Although Hib remains relatively uncommon in Calgary, the memo underscores the significance of understanding the distinctive epidemiology of this particular strain. Symptoms of Hib, although resembling flu-like symptoms, can lead to severe complications, including bloodstream infections and organ involvement that may result in fever, drowsiness, vomiting, and potentially fatal outcomes.
Dr. Monty Ghosh, an addictions and internal medicine specialist and assistant professor at the University of Calgary and University of Alberta, pointed out that factors like overcrowded living conditions, limited access to healthcare and hygiene facilities, and compromised immune systems contribute to the higher prevalence of infections among homeless populations. Hib typically spreads through respiratory droplets or sharing of personal items.
In response to the situation, Alberta’s Primary and Preventative Health Services ministry has enhanced surveillance for Hib and initiated contact tracing measures to contain its spread. The healthcare system is not expected to face significant strain from this development, but vigilance and proactive measures are crucial in addressing potential risks associated with Hib infections among vulnerable populations.