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This article examines the complicated terrain of immunization acceptance and access among Indigenous peoples in northern Ontario by drawing on conversations held prior to 2019 that explored knowledge about Haemophilus influenzae type a (Hia) infection specifically and attitudes toward vaccines more broadly. In the decade preceding COVID-19, Hia emerged as a leading cause of morbidity and mortality in Indigenous communities in northern Canada. Before developing new vaccines, it is imperative to hold conversations with the communities most affected and to learn more about Indigenous peoples' perceptions of and knowledge about vaccines, both generally and Hia specifically. We conducted focus groups and one-on-one conversations with Anishinaabe Peoples in northwestern Ontario. Our findings illustrate that decisions to vaccinate are informed by a host of social, institutional, and ideological factors and historical and contemporary relationships with government institutions and health practitioners. In particular, Indigenous community members perceived their relationships with social and health services and education institutions as coercive. Thus, public health approaches cannot continue to operate in ways that prioritize interventions for Indigenous peoples and communities so that they "do the right thing." More emphasis is needed on health service and social service provider knowledge, skills, attitudes and practices-redirecting the onus onto those within the health care system. Solutions must respect Indigenous nationhood and the right of self-determination. Finally, we suggest the term vaccine hesitancy may not entirely capture the breadth of experiences that many Indigenous Peoples and communities have and continue to have within the health care system in Canada., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sanders et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Haemophilus influenzae serotype a (Hia) has recently emerged as an important cause of invasive disease in the North American Arctic and Sub-Arctic regions, mainly affecting young Indigenous children. In this study, we addressed the question of whether the prevalence of Hia and all H. influenzae in the nasopharynx differed between paediatric populations from regions with high versus low incidence of invasive Hia disease. Nasopharyngeal specimens from children with acute respiratory tract infections (ARTI) collected for routine diagnostic detection of respiratory viruses were analysed with molecular-genetic methods to identify and serotype H. influenzae . In Nunavut, a region with a high incidence of invasive Hia disease, all H. influenzae and particularly Hia were found in the nasopharynx of 60.6% and 3.0% children. In Southern Ontario (Hamilton region), where Hia invasive disease is rare, the frequencies of all H. influenzae and Hia detection were 38.5% and 0.6%, respectively. In both cohorts, non-typeable H. influenzae was prevalent (57.0% and 37.9%, respectively). Considering that Hia is an important cause of severe invasive disease in Nunavut children, 3% prevalence of Hia among children with ARTI can reflect continuing circulation of the pathogen in the Northern communities that may result in invasive disease outbreaks.

In the post- Haemophilus influenzae type b (Hib) vaccine era, invasive H. influenzae type a (Hia) disease emerged in North American Indigenous populations. The role of Hia in noninvasive disease is uncertain; it is unknown whether noninvasive Hia infections are prevalent in populations with a high incidence of invasive disease, and whether invasive and noninvasive Hia isolates have different characteristics. We analyzed all invasive and noninvasive clinical H. influenzae isolates collected in a northwestern Ontario hospital serving 82% Indigenous population over 5.5 years. Serotyping, clonal analysis, and antimicrobial sensitivity testing were conducted on 233 noninvasive and 20 invasive isolates. Among noninvasive isolates, 91% were nontypeable (NTHi) and 3% were Hia; Hia was the most frequent invasive isolate (60%). Incidence rates of invasive H. influenzae disease (12.5/100 000/year) greatly exceeded average provincial data, with the highest found in <6-year-old children (63.9/100 000/year); the proportion of Hia among invasive isolates was seven times larger than in Ontario. No difference in clonal characteristics between invasive and noninvasive Hia isolates was found. Antibiotic resistance was more common among NTHi than among encapsulated isolates, without differences between invasive and noninvasive isolates. Considering the significance of Hia in Indigenous populations, pediatric immunization against Hia will be useful to prevent serious infections in young Indigenous children., Competing Interests: The authors declare there are no competing interests.

Despite the use of pneumococcal conjugate vaccines for pediatric immunization, North American Indigenous populations continue to experience high burden of pneumococcal infections. Naturally acquired antibodies, which can protect unvaccinated adults against pneumococcal infections, have not previously been studied in Canadian Indigenous people. We analysed concentrations of natural serum IgG, IgM and IgA antibodies specific to 7 serotype-specific capsular polysaccharides (3, 6B, 9V, 14, 19A, 19F and 23F) in 141 healthy individuals (age between 18 and 80 years), including Indigenous adults living in 2 geographical different areas of Ontario, Canada, and non-Indigenous residing in northwestern Ontario. Regardless of the geographical area, concentrations of IgG specific to serotypes 6B, 9V, and 14, IgM specific to 9V, and all serotype-specific IgA were significantly higher in Indigenous study participants as compared to non-Indigenous. The differences are likely attributed to an increased exposure of Indigenous individuals to Streptococcus pneumoniae and/or cross-reactive antigens of other microorganisms or plants present in the environment. Although in non-Indigenous adults concentrations of IgM specific to 9V, 19A, 19F, and 23F significantly decreased with age, this was not observed in Indigenous individuals suggesting that Indigenous people may experience continuous exposure to pneumococci and cross-reactive antigens over the life span. Women had generally higher concentrations of natural IgG and IgM concentrations than men, with more striking differences found in Indigenous adults, potentially associated with larger exposure of women to young children, the major reservoir of pneumococci in communities. Our data suggest that increased rates of pneumococcal infections among Indigenous people are unlikely related to deficiency of naturally acquired antibodies, at least those specific to 7 common serotypes. Determining serological correlates of protection for adults will be essential to identify the groups in need of adult pneumococcal immunizations that may prevent excessive burden of the disease among North American Indigenous people., Competing Interests: Marina Ulanova received research funding from Pfizer through a grant for Investigator Initiated Research Project to her institution, honoraria for serving on the advisory boards, and travel expenses from Pfizer. This does not alter our adherence to PLOS ONE policies on sharing data and materials. All other authors have declared that no competing interests exist.

On March 9, 2019, a one-day workshop titled "The current epidemiology of invasive Haemophilus influenzae disease in the Americas", jointly organized by the Public Health Agency of Canada (PHAC), the Canadian Institute of Health Research (CIHR), and the National Research Council Canada (NRC), brought together experts in the epidemiology and surveillance of invasive Haemophilus influenzae (Hi) disease from the Pan American Health Organization (PAHO) and its five regional reference laboratories in South America, USA, and Canada in Ottawa, Ontario, Canada. This workshop built upon recommendations of previous related workshops and incorporated updated data., (Copyright © 2020.)

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.

Background: Despite the use of pneumococcal vaccines, indigenous populations are consistently disproportionately affected by invasive pneumococcal disease (IPD). With recent changes in Ontario's provincial pneumococcal vaccination program, we sought to evaluate the epidemiology and burden of IPD in northwestern Ontario (NWO) Canada - a region that contains a substantial (19.2%) indigenous population., Methods: We retrospectively reviewed all adult cases of IPD that were reported to the Thunder Bay District Health Unit, in Thunder Bay, Ontario, Canada, over a 10-year period (2006-2015). Patients admitted to the Thunder Bay Regional Health Sciences Centre with IPD had their charts reviewed to abstract clinical data. Statistical analysis, including incidence rates of IPD, was performed., Results: Two hundred sixty-two cases of IPD occurred over the 10-year observation period and clinical data was available for 182 cases. Fifty-three of 182 (29.1%) patients were indigenous. 73 of 182 (40.1%) of patients were immunocompromised. Indigenous patients with IPD were more likely to be immunocompromised than non-indigenous patients (p < 0.001). Serotype data was available for 159 cases of IPD; PCV7, PCV13, and PPV23 covered 5.7%, 28.3%, and 79.2% of isolates, respectively, while 29 (20.8%) were non-vaccine serotypes. The annual incidence rate of IPD ranged from 8.9 to 25.9 per 100,000 among adults 18-64 years old; among adults 65 years of age and older the annual incidence of IPD ranged from 18.5 to 60.7 per 100,000., Conclusion: Among adults in NWO, Canada, there is a high incidence of IPD. Immunocompromised indigenous adults in NWO may benefit from pneumococcal vaccination coverage. Emerging non-vaccine serotypes of Streptococcus pneumoniae warrant the consideration of the provincial pneumococcal vaccination program.

Introduction: North American indigenous populations experience a high burden of invasive bacterial infections. Because Streptococcus pneumoniae and Haemophilus influenzae have multiple antigenic variants, the existing vaccines cannot prevent all cases. This study addresses the current epidemiology of invasive H. influenzae and pneumococcal disease (IPD) in a region of Northwestern Ontario, Canada with a relatively high (82%) indigenous population., Methods: Data were retrieved from a retrospective chart review at a hospital servicing a population of 29000 (82% indigenous), during January 2010-July 2015., Results: Ten cases of invasive H. influenzae disease and 37 cases of IPD were identified. The incidence of both in the study population (6.3 and 23.1/100000/year, respectively) exceeded national rates (1.6 and 9.0/100000/year). H. influenzae serotype a (Hia) was the most common (50%), followed by non-typeable H. influenzae (20%). In adults, 77% of IPD cases were caused by serotypes included in the 23-valent pneumococcal polysaccharide vaccine. All paediatric IPD cases were caused by serotypes not included in the 13-valent pneumococcal conjugate vaccine. The case-fatality rate was 10% for invasive H. influenzae and 2.7% for IPD. Most cases exhibited substantial co-morbidity., Conclusions: In Northwestern Ontario, the incidence of invasive Hia disease exceeds that of H. influenzae type b (Hib) in the pre-Hib vaccine era. This provides strong support for the development of a new Hia vaccine. Improved pneumococcal vaccination of high-risk adults in the region is warranted., (Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Northwestern Ontario is a large rural area with a high concentration of remote First Nations communities. In Ontario, the highest hospital admission rates for pneumonia are reported from northern and rural regions. However, data are lacking on the epidemiology of community-acquired pneumonia in northwestern Ontario. We sought to characterize cases of community-acquired pneumonia requiring admission at the Sioux Lookout Meno Ya Win Health Centre, which serves a primarily First Nations population of 28,000., Methods: We undertook a 3-year review of cases of community-acquired pneumonia requiring hospital admission at the centre. We used multivariable logistic regression to identify independent variables predictive of adverse outcomes., Results: The annual incidence of hospital admissions related to community-acquired pneumonia was 3.42 per 1000 population. Of the 287 patients, 87% were First Nations and 52% were female. There was a high prevalence of diabetes, and chronic cardiovascular, renal and pulmonary diseases. Hospital admissions for community-acquired pneumonia were most prevalent among young children and older adults; both age groups had low coverage with recommended pneumococcal vaccines. Adverse outcomes included 10 deaths (3%) and 35 transfers to an intensive care facility (12%). Chronic renal disease and nonreceipt of azithromycin at initial presentation were identified as 2 independent predictors of an adverse outcome; there was a trend toward an increased risk of an adverse outcome in individuals with chronic obstructive pulmonary disease., Conclusion: Our findings emphasize the importance of preventing pneumonia in First Nations communities in northwestern Ontario. Research focusing on the distinct epidemiology of community-acquired pneumonia in this population is needed.

Seven epidemiologically unrelated cases of invasive Haemophilus influenzae type a (Hia) disease were identified in First Nations communities of Northwestern Ontario, Canada, in 2004-2008. In all cases, Hia was isolated from blood. The clinical presentation in most of the cases was moderately severe and all patients responded to antibiotic therapy. Laboratory analysis of Hia isolates from Northwestern Ontario indicated striking similarities in their phenotypic and genotypic characteristics. The findings are discussed in the context of current epidemiology of invasive Hia disease. Our data along with some published studies by others suggest an increased susceptibility to this infection among North American indigenous populations.

A high incidence of invasive non-type b Haemophilus influenzae disease was found in Northwestern Ontario, Canada; H. influenzae type a was the most prevalent serotype (42%). Clinical and demographic analyses indicate that aboriginal children aged <5 years and adults with predisposing medical conditions are the most affected by invasive H. influenzae disease in the post-H. influenzae vaccine era.