Continuing surveillance of invasive Haemophilus influenzae disease in Northwestern Ontario emphasizes the importance of serotype a and non-typeable strains as causes of serious disease: A Canadian Immunization Research Network (CIRN) Study

• Main Authors: Cerqueira, Ashley, Byce, Sarah, Tsang, Raymond S.W., Jamieson, Frances B, Kus, Julianne V., Ulanova, Marina
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2019
• Subjects: Canada; inuit
• Online Access: http://hdl.handle.net/1807/96420; http://www.nrcresearchpress.com/doi/abs/10.1139/cjm-2019-0210

In the post-Haemophilus influenzae serotype b (Hib) vaccine era, invasive H. influenzae serotype a (Hia) disease emerged in Canadian First Nation, Inuit, and Alaskan Indigenous populations. Previous studies by our group found a high incidence of invasive Hia disease in northwestern Ontario. We retrospectively reviewed 24 cases (4 pediatric and 20 adult) of invasive H. influenzae disease hospitalized at the northwestern Ontario regional hospital between August 2011 and June 2018. The objectives were to further document the changing epidemiology of invasive H. influenzae disease in the region and to discuss potential control measures. Twenty-two H. influenzae isolates were serotyped and characterized using molecular-biological methods. Of the serotyped cases, there were 2 Hib, 9 Hia, and 11 non-typeable (NTHi). All Hia isolates belonged to the most common sequence types (ST) found in Canada (ST-23 and ST-929); 8 out of 9 were pan susceptible to antibiotics. One (11%) of 9 Hia and 5 (45%) of 11 NTHi cases were fatal. Our data on the consistent presence of serious invasive H. influenzae disease, with 41% prevalence of Hia (9 out of 22 serotyped isolates) and 50% prevalence of NTHi strains (11 out of 22), emphasize the importance of continued surveillance of H. influenzae in the post-Hib vaccine era and are critical information to inform potential vaccine development. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.