Pertussis epidemiology in Canada, 2005-2019.

Background: Pertussis, also known as whooping cough, is an endemic vaccine-preventable disease that affects the respiratory tract and is caused by the bacterium Bordetella pertussis. Between 1999 and 2004, the adolescent booster dose of pertussis was introduced across Canada. This report describes the epidemiology of pertussis in Canada from 2005 to 2019, the period after adolescent acellular vaccination was recommended. Methods: We analyzed pertussis incidence by year, age groups, sex and geographic region using national surveillance data from the Canadian Notifiable Disease Surveillance System. Hospitalization data from the Discharge Abstract Database was used to investigate pertussis hospitalizations by sex and age. Deaths from pertussis were explored using Statistics Canada's vital statistics data. Vaccination coverage data was gathered from the 2019 Childhood National Immunization Coverage Survey and 2018-2019 Seasonal Influenza Vaccination Coverage Survey. Results: Between 2005 and 2019, there were a total of 33,481 pertussis cases with the average annual incidence rate of 6.4 cases per 100,000 population. The highest average age-specific incidence rate was among infants under one year of age (n=68.7 cases per 100,000 population). There were a total of 1,593 pertussis hospitalizations; nearly 80% of these hospitalizations were infants under one year of age. Hospitalization rates were 8.2 times higher in infants three months or younger compared to infants four to 11 months of age. There were 17 deaths; all among infants under one year of age. Conclusion: The highest morbidity and fatality of pertussis were among infants under one year of age. It is important to take measures to reduce transmission to infants who are too young to be vaccinated. Increasing vaccine coverage in children and pregnant women are important to reduce the burden of disease.

Epidemiology of tetanus in Canada, 1995-2019.

OBJECTIVES: This report aims to use tetanus hospitalization data to describe the epidemiology in Canada from 1995 to 2019 and to assess progress on national reduction targets, including validating that Canada has eliminated maternal and neonatal tetanus (MNT). METHODS: Tetanus hospitalizations and fatalities occurring between 1995 and 2019 were retrieved from the Canadian Institute for Health Information (CIHI) and Statistics Canada. Cases coded with ICD-10 codes A33, A34, or A35 as the primary diagnosis (or ICD-9 equivalents) were included. The Canadian national case definition was used for generic tetanus and definitions from the World Health Organization were referenced for MNT. R version 4.0.2 was used for analyses. RESULTS: From 1995 to 2019, 155 non-MNT, 6 neonatal, and 0 maternal tetanus cases were retrieved from CIHI. However, all 6 neonatal cases were excluded after validating with provincial/territorial public health officials. In the same time period, there were 91 national notifications of tetanus. Cases were distributed relatively equally across the country, with the exception of the territories, where zero cases were reported. Adults 75 and over had significantly higher incidence rates compared to younger age groups (p<0.001). Ten deaths were reported during the timeframe. CONCLUSION: Tetanus incidence remains low and hospitalization data reveal that Canada has met its reduction target of maintaining 5 cases or fewer annually in recent years. For MNT, Canada has successfully met the elimination target of zero cases. Continued vaccination efforts must be practiced for all age groups, including those aged 75 years and older, to sustain targets moving forward.

RéSUMé: OBJECTIFS: Ce rapport vise à utiliser les données sur les hospitalisations dues au tétanos pour décrire l'épidémiologie au Canada de 1995 à 2019 et pour évaluer les progrès réalisés par rapport aux objectifs nationaux de réduction, notamment pour confirmer que le Canada a éliminé le tétanos maternel et néonatal (TMN). MéTHODES: Les données sur les hospitalisations et les décès attribuables au tétanos survenus entre 1995 et 2019 proviennent de l'Institut canadien d'information sur la santé (ICIS) et de Statistique Canada. Les cas pour lesquels les codes sont CIM-10 A33, A34 ou A35 comme diagnostic primaire (ou leurs équivalents CIM-9) sont inclus. La définition de cas nationale canadienne a été utilisée pour le tétanos générique et les définitions de l'Organisation mondiale de la santé ont servi de référence pour le TMN. La version 4.0.2 de R a été utilisée pour les analyses. RéSULTATS: De 1995 à 2019, il y a eu 155 cas de tétanos autres que TMN, 6 cas de tétanos néonatal et 0 cas de tétanos maternel selon l'ICIS. Cependant, les 6 cas de tétanos néonatal ont été exclus après validation auprès des responsables de la santé publique provinciaux/territoriaux. Durant la même période, il y a eu 91 notifications nationales de cas de tétanos. Ces cas étaient répartis de manière relativement égale à travers du pays, à l'exception des territoires, où aucun cas n'a été signalé. Les adultes de 75 ans et plus présentaient des taux d'incidence significativement plus élevés que les groupes d'âge plus jeune (p<0,001). Dix décès ont été rapportés pendant cette période. CONCLUSION: L'incidence du tétanos reste faible et les données sur les hospitalisations révèlent que le Canada a atteint son objectif de réduction de 5 cas ou moins par an au cours des dernières années. En ce qui concerne le TMN, le Canada a réussi à atteindre l'objectif d'élimination des cas. Il faut poursuivre les efforts de vaccination pour tous les groupes, y compris les personnes âgées de 75 ans et plus, afin de maintenir les objectifs à l'avenir.

Epidemiology of invasive meningococcal disease in Canada, 2012-2019.

Background: A variety of routine childhood and adolescent meningococcal vaccination programs using monovalent (serogroup C) and quadrivalent (A, C, Y, W) conjugate vaccines have been implemented in Canada since 2002, resulting in a decrease in invasive meningococcal disease (IMD) incidence, particularly in serogroup C. Meningococcal vaccines have also been used for outbreak response, including the multicomponent vaccine serogroup B vaccine. This report describes the epidemiology of IMD in Canada from 2012 to 2019. Methods: Case data were obtained from the National Enhanced IMD Surveillance System between January 1, 2012 and December 31, 2019. Isolates were sent to the National Microbiology Laboratory for confirmation of serogroup and further studies including phenotype and clonal complex identification. Results: A total of 983 cases of IMD were reported between 2012 and 2019. Overall, the age-adjusted incidence of IMD from 2012 to 2019 was 0.34 cases per 100,000 population per year when standardized to the Canadian 2011 population age distribution (95% CI: 0.32-0.36). Infants younger than one year of age had the highest average age-specific incidence rate (3.6 cases per 100,000 population per year, 95% CI: 2.8-4.3). The highest age-adjusted incidence rate was associated with serogroup B (0.17 cases per 100, 000 population per year, 95% CI: 0.16-0.19). Prior to 2015, most invasive serogroup W isolates were identified as clonal complex 22 (ST-22 CC) and the increase in serogroup W in Canada in recent years has been associated with the replacement of the endemic ST-22 CC with the hyper-virulent ST-11 CC. Conclusion: Invasive meningococcal disease is a rare but severe infection in Canada that mostly affects the very young. Serogroup B continues to account for the greatest proportion of disease. Serogroup W associated with ST-11 CC is becoming a growing contributor of disease in all age groups not protected by serogroup W-containing vaccines.

Invasive bacterial diseases in northern Canada, 1999 to 2018.

BACKGROUND: The International Circumpolar Surveillance (ICS) program conducts surveillance on five invasive bacterial diseases: pneumococcal disease (IPD), group A streptococcus (iGAS), Haemophilus influenzae (Hi), meningococcal disease (IMD) and group B streptococcus (GBS). Invasive bacterial diseases have a higher burden of disease in northern populations than the rest of Canada. METHODS: To describe the epidemiology of invasive bacterial diseases in northern Canada from 1999 to 2018, data for IPD, iGAS, Hi, IMD and GBS were extracted from the ICS program and the Canadian Notifiable Diseases Surveillance System (CNDSS) and analyzed. RESULTS: The annualized incidence rates for IPD, iGAS, Hi, GBS and IMD were 23.3, 10.5, 8.9, 1.9 and 1.1 per 100,000 population, respectively. The incidence of IPD, iGAS and Hi serotype b were 2.8, 3.2 and 8.8 times higher, respectively, in northern Canada than in the rest of Canada. Rates of disease decreased statistically significantly for IPD (ß=-0.02) and increased statistically for iGAS (ß=0.08) and Hi serotype a (ß=0.04) during the study period. In Northern Canada, the annualized incidence rates for IPD, iGAS and Hi were statistically higher for Indigenous residents than for non-Indigenous residents. The highest incidence rates were among the very young and older age groups. CONCLUSION: Invasive bacterial diseases represent a high burden of disease in Canada's northern populations. Indigenous peoples, children and seniors are particularly at risk.

Multisystem inflammatory syndrome in children in Canada.

This article provides a summary of the epidemiology of multisystem inflammatory syndrome in children (MIS-C) cases reported nationally in Canada by provincial and territorial health authorities. Multisystem inflammatory syndrome in children is a post-viral inflammatory syndrome that temporally follows coronavirus disease 2019 (COVID-19). Symptoms may include fever, abdominal pain, vomiting, diarrhea, skin rash and other signs of inflammation. In Canada, MIS-C is rare, with 269 cases reported to the Public Health Agency of Canada between March 11, 2020 and October 2, 2021. One hundred forty-two (53%) of these cases were lab-confirmed COVID-19 cases or epidemiologically-linked with COVID-19 cases. Cases have been reported in infants as young as one week to youth as old as 18 years, with a median age of six years. Cases were more likely to occur in males than females (58% vs 42%, respectively; p=0.006). Almost all MIS-C cases (99%) required hospitalization and 36% required intensive care unit admission. No deaths have been reported to date. The time trend of MIS-C aligns with the incidence rate time trend of COVID-19 reported in children, with a two to six-week lag.

Laboratory characterization of invasive Haemophilus influenzae isolates from Nunavut, Canada, 2000-2012.

BACKGROUND: With invasive Haemophilus influenzae serotype b (Hib) disease controlled by vaccination with conjugate Hib vaccines, there is concern that invasive disease due to non-serotype b strains may emerge. OBJECTIVE: This study characterized invasive H. influenzae (Hi) isolates from Nunavut, Canada, in the post-Hib vaccine era. METHODS: Invasive H. influenzae isolates were identified by conventional methods at local hospitals; and further characterized at the provincial and federal public health laboratories, including detection of serotype antigens and genes, multi-locus sequence typing and antibiotic susceptibility. RESULTS: Of the 89 invasive H. influenzae cases identified from 2000 to 2012, 71 case isolates were available for study. There were 43 serotype a (Hia), 12 Hib, 2 Hic, 1 Hid, 1 Hie, 2 Hif and 10 were non-typeable (NT). All 43 Hia were biotype II, sequence type (ST)-23. Three related STs were found among the Hib isolates: ST-95 (n=9), ST-635 (n=2) and ST-44 (n=1). Both Hif belonged to ST-124 and the 2 Hic were typed as ST-9. The remaining Hid (ST-1288) and Hie (ST-18) belonged to 2 separate clones. Of the 10 NT strains, 3 were typed as ST-23 and the remaining 7 isolates each belonged to a unique ST. Eight Hib and 1 NT-Hi were found to be resistant to ampicillin due to ß-lactamase production. No resistance to other antibiotics was detected. CONCLUSION: During the period of 2000-2012, Hia was the predominant serotype causing invasive disease in Nunavut. This presents a public health concern due to an emerging clone of Hia as a cause of invasive H. influenzae disease and the lack of published guidelines for the prophylaxis of contacts. The clonal nature of Hia could be the result of spread within an isolated population, and/or unique characteristics of this strain to cause invasive disease. Further study of Hia in other populations may provide important information on this emerging pathogen. No antibiotic resistance was detected among Hia isolates; a small proportion of Hib and NT-Hi isolates demonstrated resistance to ampicillin due to ß-lactamase production.

The prevalence of human papillomavirus and its impact on cervical dysplasia in Northern Canada.

INTRODUCTION: Certain types of the Human Papillomavirus (HPV) are sexually transmitted and highly associated with development of cervical dysplasia and cervical cancer but the distribution of HPV infection in the North, particularly amongst First Nations, Metis, and Inuit peoples, is little known. The purposes of the study are to identify the prevalence of type-specific HPV infections and the association of different HPV types with cervical dysplasia among women in Northern Canada. METHODS: This was a cross-sectional study with attendants of the routine or scheduled Pap testing program in the Northwest Territories (NWT), Nunavut, Labrador and Yukon, Canada. Approximately half of each sample was used for Pap test and the remaining was used for HPV genotyping using a Luminex-based method. Pap test results, HPV types, and demographic information were linked for analyses. RESULTS: Results from 14,598 specimens showed that HPV infection was approximately 50% higher among the Aboriginal than the non-Aboriginal population (27.6% vs. 18.5%). Although the most common HPV type detected was HPV 16 across region, the prevalence of other high risk HPV types was different. The age-specific HPV prevalence among Aboriginal showed a 'U' shape which contrasted to non-Aboriginal. The association of HPV infection with cervical dysplasia was similar in both Aboriginal and non-Aboriginal populations. CONCLUSIONS: The HPV prevalence was higher in Northern Canada than in other Areas in Canada. The prevalence showed a higher rate of other high risk HPV infections but no difference of HPV 16/18 infections among Aboriginal in comparison with non-Aboriginal women. This study provides baseline information on HPV prevalence that may assist in surveillance and evaluation systems to track and assess HPV vaccine programs.

Patterns of reporting by health care and nonhealth care professionals to child protection services in Canada.

BACKGROUND: All Canadian jurisdictions require certain professionals to report suspected or observed child maltreatment. The present study examined the types of maltreatment, level of harm and child functioning issues (controlling for family socioeconomic status, age and sex of the child) reported by health care and nonhealth care professionals. METHODS: χ(2) analyses and logistic regression were conducted on a national child welfare sample from the 2003 Canadian Incidence Study of Reported Child Abuse and Neglect (CIS-2003), and the differences in professional reporting were compared with its previous cycle (CIS-1998) using Bonferroni-corrected CIs. RESULTS: Analysis of the CIS-2003 data revealed that the majority of substantiated child maltreatment was reported to service agencies by nonhealth care professionals (57%), followed by other informants (33%) and health care professionals (10%). The number of professional reports increased 2.5 times between CIS-1998 and CIS-2003, while nonprofessional reports increased 1.7 times. Of the total investigations, professional reports represented 59% in CIS-1998 and 67% in CIS-2003 (P<0.001). Compared with nonhealth care professionals, health care professionals more often reported younger children, children who experienced neglect and emotional maltreatment, and those assessed as suffering harm and child functioning issues, but less often reported exposure to domestic violence. CONCLUSION: The results indicate that health care professionals play an important role in identifying children in need of protection, considering harm and other child functioning issues. The authors discuss the reasons why under-reporting is likely to remain an issue.