Trends in Cemented Fixation in Hemiarthroplasty for Hip Fractures in Canada.

Bacground: The use of cemented fixation is widely recommended in hip arthroplasty for hip fractures, although it is not used universally. Methods: We describe the trends in cementing prevalence in hemiarthroplasty for hip fractures in Canada for patients ≥55 years old between April 2017 and March 2022. Results: The national prevalence of cemented fixation increased from 43% in 2017/18 to 58% in 2021/22, but there was a large variety of both the baseline prevalence and the trends across the country and between individual hospitals. The proportion of surgeons only performing cementless fixation fell from 30% to 21% between 2018/19 and 2021/22. Conclusions: As cemented fixation is now universally recommended, more coordination is needed to track these trends and to help drive implementation of this evidence-based practice across Canada.

Leveraging a clinical emergency department dataset to estimate two-dose COVID-19 vaccine effectiveness and duration of protection in Canada.

BACKGROUND: During the COVID-19 pandemic, clinical care shifted toward virtual and Emergency Department care. We explored the feasibility of mRNA vaccine effectiveness (VE) estimation against SARS-CoV-2-related Emergency Department visits and hospitalizations using prospectively collected Emergency Department data. METHODS: We estimated two-dose VE using a test-negative design and data from 10 participating sites of the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN). We included Emergency Department patients presenting with COVID-19 symptoms and nucleic acid amplification testing for SARS-CoV-2 between July 19 and December 31, 2021. We excluded patients with unclear vaccination and one or more than 2 vaccine doses by their Emergency Department visit. RESULTS: Among 3,405 eligible patients, adjusted two-dose mRNA VE against SARS-CoV-2-related Emergency Department visits was 93.3 % (95 % CI 87.9-96.3 %) between 7-55 days, sustained over 80 % through 139 days post-vaccination. In stratified analyses, VE was similar among patients with select immune-compromising conditions, chronic kidney disease, lung disease, unstable housing, and reported illicit substance use. CONCLUSIONS: Two-dose mRNA VE against SARS-CoV-2-related Emergency Department visit was high and sustained, including among vulnerable subgroups. Compared to administrative datasets, active Emergency Department enrolment enables standardization for testing access and indication and supports separate VE assessment among special population subgroups. Compared to other active enrolment settings, Emergency Departments more consistently function during crises when alternate healthcare sectors become variably closed. TRIAL REGISTRATION: Clinicaltrials.gov, NCT0470294.

Consistent Factors Influence Body Mass Index Thresholds for Total Joint Arthroplasty Across Health-Care Systems: A Qualitative Study.

BACKGROUND: Body mass index (BMI) thresholds are used as eligibility criteria to reduce complication risk in total joint arthroplasty (TJA). This approach oversimplifies preoperative risk assessment and inadvertently restricts access to effective surgical treatment for osteoarthritis. A prior survey of orthopaedic surgeons in the United States identified complex underlying factors that influence BMI considerations. To understand whether similar factors exist and influence surgeons in a different health-care system setting, we investigated Canadian surgeons' views and use of BMI criterion thresholds for TJA access. METHODS: A cross-sectional online qualitative survey was conducted with orthopaedic surgeons performing TJA in the Canadian health-care system. Responses were anonymous and questions were open-ended to allow for candid perspectives. Survey data were coded and a systematic process was followed to identify major themes. Findings were compared with U.S. surgeon perspectives. RESULTS: Sixty-nine respondents had a mean age of 49.0 ± 11.4 years (range, 33 to 79 years), with a mean surgical experience duration of 15.7 ± 11.4 years (range, 2 to 50 years). Surgeons reported variable use of BMI thresholds in practice. Twelve interconnected factors that influence BMI considerations were identified: (1) variable evidence interpretation, (2) surgical challenge, (3) surgeon beliefs and biases, (4) hospital differences, (5) access to resources, (6) health system bias, (7) patient health status, (8) patient body fat distribution, (9) patient decisional burden (to lose weight or accept risk), (10) evidence gaps and uncertainties, (11) need for innovation, and (12) societal views. Nine themes matched with findings from U.S. surgeons. CONCLUSIONS: Parallel to the United States, complex, interconnected factors influence Canadian orthopaedic surgeons' variable use of BMI restrictions for TJA eligibility. Despite different health-care systems and reimbursement models, similar technical and personal factors were identified. With TJA practice guidelines advising against hard BMI criteria, attention regarding access to resources, surgical training, and innovations to address TJA complexity in patients with large bodies are critically needed. Future advancements in this sphere must balance barrier removal with risk reduction to ensure safe and equitable surgical care. CLINICAL RELEVANCE: This study may influence surgeon behaviors with regard to hard BMI cutoffs for TJA and encourage critical thought about factors that influence decisions about surgical eligibility for patients with high BMI.

Socioeconomic, health-related, and primary care physician characteristics associated with adherence to seasonal influenza vaccination in Manitoba, Canada: A population-wide record-linkage cohort study.

OBJECTIVE: There is a lack of published evidence on factors associated with adherence (maintenance of cumulative vaccination) to seasonal influenza vaccination (SIV) in Manitoba, Canada. We sought to assess the associations. METHODS: A cohort study utilizing Manitoba administrative health databases. Participants received SIV in 2010/11 influenza season, remained registered Manitoba residents and received at least one SIV during the 2011/12‒2019/20 seasons. We dichotomized adherence into "more adherent" (6‒9 SIVs) and "less adherent" (1‒5 SIVs) and used multivariable adjusted generalized estimating equation logistic regression models to assess association between adherence and socioeconomic, health-related, and primary care physician (PCP) characteristics, stratified by age group (< 5, 5‒17, 18‒44, 45‒64, ≥ 65) and sex. Results are adjusted odds ratios with 95% confidence intervals. RESULTS: There were 152,493 participants. Males had lower odds of being more adherent except among ≥ 65-year-olds (1.03, 95% CI 1.01‒1.05). Compared with the lowest income quintile, those in higher income quintiles had higher odds of being more adherent. The odds mostly increased with increase in income quintile. Those with more contact with their PCP/hospitalization one year prior had higher odds of being more adherent. The odds increased with increased contact among those 18‒44, 45‒64 and ≥ 65 years old. Those who had PCP with more years of practice had higher odds of being more adherent. The odds increased as years of practice increased. These observations were mostly consistent irrespective of sex. CONCLUSION: Female gender, having higher income, having more contact with the health system, and having an experienced PCP may determine increased adherence to SIV in Manitoba. These findings require attention.

RéSUMé: OBJECTIF: Il y a un manque de données publiées sur les facteurs associés à l'adhésion vaccinale (le maintien de la vaccination cumulée) pour le vaccin contre la grippe saisonnière (VGS) au Manitoba (Canada). Nous avons cherché à évaluer ces associations. MéTHODE: Étude de cohorte utilisant les bases de données administratives sur la santé du Manitoba. Les participantes et les participants ont reçu le VGS durant la saison grippale 2010‒2011, ont continué d'être des résidents inscrits du Manitoba et ont reçu au moins un VGS au cours des saisons 2011‒2012 à 2019‒2020. Nous avons dichotomisé l'adhésion en « adhésion importante ¼ (6 à 9 VGS) et en « faible adhésion ¼ (1 à 5 VGS) et utilisé des modèles de régression logistique ajustés multivariés avec des équations d'estimation généralisées pour déterminer l'association entre l'adhésion et les caractéristiques liées au statut socioéconomique, à l'état de santé et au médecin de premier recours (MPR), stratifiées par groupe d'âge (< 5 ans, 5‒17 ans, 18‒44 ans, 45‒64 ans et ≥ 65 ans) et par sexe. Les résultats sont des rapports de cotes ajustés avec des intervalles de confiance de 95%. RéSULTATS: Il y a eu 152 493 personnes participantes. La probabilité d'une adhésion importante était inférieure chez les hommes, sauf chez les ≥ 65 ans (1,03, IC 95% 1,01‒1,05). La probabilité d'une adhésion importante était aussi plus élevée dans les quintiles de revenu supérieurs que dans le quintile de revenu inférieur. Cette probabilité augmentait principalement avec l'augmentation du quintile de revenu. Les personnes ayant eu plus de contacts avec leur MPR ou ayant été hospitalisées au cours de l'année antérieure étaient plus susceptibles d'afficher une adhésion importante. Cette probabilité augmentait avec l'augmentation des contacts dans les groupes d'âge de 18‒44 ans, de 45‒64 ans et de ≥ 65 ans. Les personnes dont le MPR exerçait depuis un grand nombre d'années étaient plus susceptibles d'afficher une adhésion importante. Cette probabilité augmentait avec le nombre d'années d'exercice. Ces observations étaient pour la plupart cohérentes quel que soit le sexe. CONCLUSION: Le sexe féminin, le revenu élevé, le fait d'avoir plus de contacts avec le système de santé et le fait d'avoir un MPR d'expérience peuvent déterminer l'adhésion accrue à la vaccination contre la grippe saisonnière au Manitoba. Ces constats méritent d'être pris en considération.

Characteristics and determinants of seasonal influenza vaccination in Manitoba, Canada: A population-wide record-linkage study.

Background: Seasonal influenza vaccine (SIV) uptake (receipt of vaccine) in Manitoba, Canada is consistently low notwithstanding vaccine availability and free-of-charge vaccination. Despite, there is a lack of published evidence on the determinants of uptake of the vaccine. We sought to assess the association between SIV uptake and certain population and primary care physician (PCP) characteristics in Manitoba. Methods: We conducted a longitudinal study utilizing Manitoba administrative health databases. We summarized SIV uptake from 2000/01-2019/20 influenza seasons across subpopulations defined by socioeconomic, health-related and PCP characteristics. Utilizing multivariable generalized estimating equation logistic regression models, we assessed the association between SIV uptake and the socioeconomic, health-related and PCP characteristics, stratified by age group (<5-, 5-17-, 18-44-, 45-64-, ≥65-year-olds) and sex. Results are adjusted odds ratios with associated 95 % confidence intervals. Results: SIV uptake percentage increased over time with 4.4 %, 13.1 %, 17.5 % and 21.7 % of < 5-year-olds, 2 %, 4.9 %, 9.7 % and 13.1 % of 5-17-year-olds, 5.4 %, 8.8 %, 10.7 % and 13.5 % of 18-44-year-olds, 16.8 %, 21.3 %, 23.6 % and 24.6 % of 45-64-year-olds receiving the SIV in 2000-2004, 2005-2009, 2010-2014 and 2015-2019, respectively. There was a decline among ≥ 65-year-olds from 58.5 % to 53.5 %. We observed a similar pattern across subpopulations. There were significantly increased odds of SIV uptake among females within the age groups ≥ 18 years, in higher income quintiles, mostly with increased contact with a PCP/hospitalization within age groups ≥ 18 years, among those who had older or female PCPs (the opposite observation among ≥ 65-year-olds) and whose PCP administered at least one SIV in prior influenza season. These observations were largely consistent irrespective of sex. Conclusion: SIV uptake in Manitoba appears to increase with age, and many socioeconomic, health-related and PCP characteristics appear to be associated with it. These findings may inform targeted vaccination programs to optimize influenza vaccination in Manitoba and similar Canadian jurisdictions.

A population-based, province-wide, record-linkage interrupted time series analysis of impact of the universal seasonal influenza vaccination policy on seasonal influenza vaccine uptake among 5-64-year-olds in the province of Manitoba, Canada.

INTRODUCTION: Universal seasonal influenza vaccination policy (USIVP) was introduced in Manitoba, Canada in 2010. Its impact on seasonal influenza vaccine (SIV) uptake remains underexplored. METHODS: We used population-wide data from Manitoba to assess the impact of the USIVP on SIV uptake. The study covered twenty influenza seasons (2000/01-2019/20). We summarized SIV uptake for influenza seasons before and after the USIVP. Utilizing a single-group interrupted time series analysis and appropriately accounting for autocorrelation, we estimated absolute change and annual trend in SIV uptake percentages among 5-17-, 18-44-, and 45-64-year-olds across strata of certain population socioeconomic and health-related characteristics following the USIVP. RESULTS: Average SIV uptake percentage in all age groups was significantly higher after compared with before the USIVP. Following the USIVP, there was no significant absolute change in SIV uptake percentage among 18-44- and 45-64-year-olds overall; however, a significant decrease was observed among 18-44-year-old males in the higher income quintiles, across healthcare utilization, and in some regions of residence. A significant increase was observed among 5-17-year-olds in the lowest income quintiles, in Northern Manitoba, and among those with less healthcare utilization, and no chronic disease. Overall, there was mostly no significant annual trend in SIV uptake percentage among 18-44-year-olds, and while a significant upward and downward trend was observed among 5-17-year-olds and 45-64-year-olds, respectively, a significant downward trend was observed across all strata of population characteristics within all age groups in Northern Manitoba. CONCLUSIONS: The USIVP in Manitoba was followed by an absolute increase in SIV uptake percentage only in some socioeconomically disadvantaged subpopulations among 5-17-year-olds. While there was mostly an upward annual trend in SIV uptake percentage among 5-17-year-olds, a downward trend was observed among 45-64-year-olds and across all age groups and subpopulations in socioeconomically disadvantaged Northern Manitoba. These findings are novel for Manitoba and require investigation and public health attention.

Randomized controlled trial comparing traditional versus enhanced-fixation designs of a novel cemented total knee arthroplasty tibial component.

Aims: A novel enhanced cement fixation (EF) tibial implant with deeper cement pockets and a more roughened bonding surface was released to market for an existing total knee arthroplasty (TKA) system.This randomized controlled trial assessed fixation of the both the EF (ATTUNE S+) and standard (Std; ATTUNE S) using radiostereometric analysis. Methods: Overall, 50 subjects were randomized (21 EF-TKA and 23 Std-TKA in the final analysis), and had follow-up visits at six weeks, and six, 12, and 24 months to assess migration of the tibial component. Low viscosity bone cement with tobramycin was used in a standardized fashion for all subjects. Patient-reported outcome measure data was captured at preoperative and all postoperative visits. Results: The patient cohort mean age was 66 years (SD seven years), 59% were female, and the mean BMI was 32 kg/m2 (SD 6 kg/m2). Mean two-year subsidence of the EF-TKA was 0.056 mm (95% confidence interval (CI) 0.025 to 0.086) versus 0.006 mm (95% CI -0.029 to 0.040) for the Std-TKA, and the two-year maximum total point motion (MTPM) was 0.285 mm (95% upper confidence limit (UCL) ≤ 0.363) versus 0.346 mm (95% UCL ≤ 0.432), respectively, for a mean difference of -0.061 mm (95% CI -0.196 to 0.074). Inducible displacement also did not differ between groups. The MTPMs between 12 and 24 months for each group was below the published threshold of 0.2 mm for predicting early aseptic loosening (p < 0.001 and p = 0.001, respectively). Conclusion: Both the enhanced fixation and the standard tibial implant design showed fixation with a predicted low risk of long-term aseptic loosening.

Regional Disparities in the Uptake of Differentiated Influenza Vaccines in the United States.

Significant racial/ethnic inequities in the uptake of differentiated influenza vaccines (DIVs) have been previously reported, though less is known about regional disparities. We conducted a retrospective longitudinal study (2014/15-2017/18 influenza seasons) among privately insured adults aged 65 + years in the US. The exposure was the beneficiary's area of residence (US Census Bureau division) and the outcome was the type of influenza vaccine: differentiated (high-dose [HDV], adjuvanted, recombinant, and cell-based) versus conventional standard-dose egg-based. Multilevel logistic regression modeling, guided by a causal diagram, was used to assess the influence of socio-demographics, medical, healthcare utilization, community, and vaccinator characteristics in confounding or mediating regional disparities. Among those vaccinated in physician offices, beneficiaries in the East North Central region were twice as likely to receive a DIV vs those in the South Atlantic, whereas those in the East and West South Central were least likely. Disparities became more pronounced in models adjusted for individual and community characteristics, suggesting that crude uptake estimates understate the true magnitude of disparities. A vaccinator's previous HDV use was most influential in explaining regional differences. Similar but less pronounced patterns emerged for vaccinations in pharmacies/facilities. Regional disparities remained even in fully adjusted models, pointing to currently poorly understood factors that may include quality of healthcare, client health literacy and engagement, and other political and cultural factors.

Comparison of two hydroxyapatite-coated femoral components: a randomized clinical trial using radiostereometric analysis.

Aims: The primary aim of this trial was to compare the subsidence of two similar hydroxyapatite-coated titanium femoral components from different manufacturers. Secondary aims were to compare rotational migration (anteversion/retroversion and varus/valgus tilt) and patient-reported outcome measures between both femoral components. Methods: Patients were randomized to receive one of the two femoral components (Avenir or Corail) during their primary total hip arthroplasty between August 2018 and September 2020. Radiostereometric analysis examinations at six, 12, and 24 months were used to assess the migration of each implanted femoral component compared to a baseline assessment. Patient-reported outcome measures were also recorded for these same timepoints. Overall, 50 patients were enrolled (62% male (n = 31), with a mean age of 65.7 years (SD 7.3), and mean BMI of 30.2 kg/m2 (SD 5.2)). Results: The two-year subsidence was similar for Avenir (-0.018 mm (95% confidence interval (CI) -0.053 to 0.018) and Corail (0.000 mm (95% CI -0.027 to 0.026; p = 0.428). Both anteversion/retroversion (Avenir 0.139° (95% CI -0.204 to 0.481°); Corail -0.196° (95% CI -0.445 to 0.053°; p = 0.110) and varus/valgus tilt (Avenir -0.024° (95% CI -0.077 to 0.028); Corail -0.049° (95% CI -0.098 to 0.000°; p = 0.473) were not statistically significantly different. After two years, patients reported similar improvements in EuroQol five-dimension five-level health questionnaire (Avenir 0.22 (SD 0.2); Corail 0.22 (SD 0.18); p = 0.965) and other outcomes scores. Patient satisfaction on a five-point Likert scale was also similar between both groups after two years (Avenir 1.38 (SD 0.88); Corail 1.33 (SD 0.57); p = 0.846). Conclusion: The performance of both femoral components was similar in terms of stability and patient outcomes.

Impact of the universal seasonal influenza vaccination policy in the province of Manitoba, Canada: A population-based, province-wide record-linkage study.

INTRODUCTION: In 2010, the government of the province of Manitoba, Canada introduced universal seasonal influenza vaccination policy (USIVP), providing free-of-charge vaccination to all registered residents of the province at least six months of age. Impact of the policy on seasonal influenza vaccine (SIV) uptake (receipt of vaccine) in Manitoba remains unclear, as there is a lack of published evaluations. METHODS: We conducted an ecological study, utilizing population-wide data from several linked de-identified Manitoba Health and Seniors Care administrative health databases. The study period was from 2000/01-2019/20 influenza seasons. The primary exposure was USIVP (five influenza seasons pre-policy [2005/06-2009/10] compared with post-policy [2010/11-2014/15]). The outcome was SIV uptake. We conducted pre/post logistic regression analysis stratified by age group (<5-, 5-17-, 18-44-, 45-64-, ≥65-year-olds) and certain population socioeconomic and health-related characteristics. Results are adjusted odds ratios with associated 95 % confidence intervals. RESULTS: We observed significantly increased adjusted odds of SIV uptake post-policy relative to pre-policy in all age groups except ≥65-year-olds already covered from inception of the vaccination programme. The adjusted odds ratios ranged from 0.76 (0.75-0.76) among ≥65-year-olds to 2.15 (2.13-2.18) among 5-17-year-olds, and were largely homogeneous within age groups across sex, income quintiles, regions of residence, and categories of number of visits to primary care physician/hospitalization one year prior to an influenza season except among <5- and 5-17-year-olds. These findings were mostly consistent irrespective of sex and region of residence although there was variability across income quintiles in Northern Manitoba region. CONCLUSIONS: Introduction of the USIVP in Manitoba was followed by a significant increase in SIV uptake in the five years post policy among <65-year-olds, with similar increased relative odds of vaccination observed within age groups across subpopulations. The observed variations in the relative odds of vaccination across income quintiles in Northern Manitoba region requires administrative attention.

Effectiveness of Coronavirus Disease 2019 Vaccines Against Hospitalization and Death in Canada: A Multiprovincial, Test-Negative Design Study.

BACKGROUND: A major goal of coronavirus disease 2019 (COVID-19) vaccination is to prevent severe outcomes (hospitalizations and deaths). We estimated the effectiveness of messenger RNA (mRNA) and ChAdOx1 COVID-19 vaccines against severe outcomes in 4 Canadian provinces between December 2020 and September 2021. METHODS: We conducted this multiprovincial, retrospective, test-negative study among community-dwelling adults aged ≥18 years in Ontario, Quebec, British Columbia, and Manitoba using linked provincial databases and a common study protocol. Multivariable logistic regression was used to estimate province-specific vaccine effectiveness against COVID-19 hospitalization and/or death. Estimates were pooled using random-effects models. RESULTS: We included 2 508 296 tested participants, with 31 776 COVID-19 hospitalizations and 5842 deaths. Vaccine effectiveness was 83% after a first dose and 98% after a second dose against both hospitalization and death (separately). Against severe outcomes, effectiveness was 87% (95% confidence interval [CI], 71%-94%) ≥84 days after a first dose of mRNA vaccine, increasing to 98% (95% CI, 96%-99%) ≥112 days after a second dose. Vaccine effectiveness against severe outcomes for ChAdOx1 was 88% (95% CI, 75%-94%) ≥56 days after a first dose, increasing to 97% (95% CI, 91%-99%) ≥56 days after a second dose. Lower 1-dose effectiveness was observed for adults aged ≥80 years and those with comorbidities, but effectiveness became comparable after a second dose. Two doses of vaccines provided very high protection for both homologous and heterologous schedules and against Alpha, Gamma, and Delta variants. CONCLUSIONS: Two doses of mRNA or ChAdOx1 vaccine provide excellent protection against severe outcomes.

Patterns and predictors of referral to the specialized chronic lymphocytic leukemia clinic in Manitoba, Canada.

BACKGROUND: Better CLL patient survival has been reported for specialized CLL clinics/hematologists (compared to other CLL patients). It is possible that improved survival is driven by a better prognosis of referred patients. METHODS: We used logistic regression to calculate the odds ratios (ORs) and 95 % confidence intervals 95 %CIs) of the association between patient characteristics and CLL referral of all persons diagnosed in 2005-2016 with a pathologically-confirmed CLL or SLL. RESULTS: Two-thirds of 1293 patients were referred to the CLL clinic. Referred patients were younger (16 % vs 44 % were 80 +) and in better health (47 % vs 56 % with a chronic diseases) than non-referred patients. Referral increased over time: in 2005-2010, about 60 % of patients were referred; in 2011-2016, this increased to 76 %. Gender did not affect referral (the OR for females is 1.0, 95 %CI 0.8-1.2), but age played a major role; CLL patients diagnosed at age 80 + were less likely to be referred than patients diagnosed < 60, 0.2 (0.1-0.3). CONCLUSION: Because referral to Manitoba's specialized CLL clinic is associated with age and the patient's overall health before referral, one should be careful in interpreting differences in outcomes between CLL patients based on referral status alone.

What explains racial/ethnic inequities in the uptake of differentiated influenza vaccines?

We investigated the role of individual, community and vaccinator characteristics in mediating racial/ethnic disparities in the uptake of differentiated influenza vaccines (DIVs; including high-dose, adjuvanted, recombinant and cell-based vaccines). We included privately-insured (commercial and Medicare Advantage) ≥65 years-old community-dwelling health plan beneficiaries in the US with >1 year of continuous coverage and who received ≥1 influenza vaccine during the study period (July 2014-June 2018). Of 2.8 million distinct vaccination claims, 60% were for DIVs; lower if received in physician offices (49%) compared to pharmacies/facilities (74%). Among those vaccinated in physician offices, non-whites had lower odds of receiving a DIV if they lived in a non-minority county (0.77;95%CI 0.75-0.80) and even lower odds if they lived in a minority county (0.62;0.60-0.63). Differences in education, household income, medical history, community and vaccinator characteristics did not fully explain the disparities. Similar patterns emerged for vaccinations in pharmacies/facilities, although disparities disappeared altogether after controlling for socio-economic and vaccinator characteristics. When vaccinated in physician offices, minority county residents were less likely to receive a DIV, especially for non-whites (0.72;0.67-0.78). These disparities disappeared for whites, but not for non-whites, after controlling for community and vaccinator characteristics. We found an alarming level of inequity in DIV vaccine uptake among fully insured older adults that could not be fully explained by differences in sociodemographic, medical, community, and vaccinator characteristics. New strategies are urgently needed to address these inequities.

Incidence of anogenital warts after the introduction of the quadrivalent HPV vaccine program in Manitoba, Canada.

BACKGROUND: The incidence of anogenital warts (AGW) decreased after the introduction of the quadrivalent human papillomavirus (qHPV) vaccine in multiple jurisdictions. We studied how comparing AGW incidence rates with different outcomes affects the interpretation of the qHPV vaccination program. To do this, we replicated multiple study designs within a single jurisdiction (Manitoba). METHODS: We measured the incidence rates of AGW, AGW-related prescriptions, chlamydia, and gonorrhea (the latter two as sham outcomes) between 2001 and 2017 using several clinical and administrative health databases from Manitoba. We then used incidence rate ratios (IRRs) to compare, for each outcome, the rate for the 1997-1998 birth cohort (the first cohorts eligible for the publicly funded qHPV vaccination program) and the older 1995-1996 birth cohort. RESULTS: AGW incidence in Manitoba dropped 72% (95% confidence interval 54-83%) among 16-18 year-old girls and 51% (14-72%) among boys after the introduction of the female-only qHPV vaccination program. Trends in AGW-related prescriptions were different from trends in AGW diagnoses as these prescriptions peaked shortly after the introduction of the publicly funded qHPV vaccine program. Chlamydia and gonorrhea incidence rates also decreased 12% (5-18%) and 16% (-1-30%), respectively, for 16-18 year-old girls. CONCLUSIONS: The publicly funded school-based qHPV vaccine program reduced AGW incidence in Manitoba by three-quarters in young females. AGW-related prescriptions are a poor proxy for medically attended AGW after the introduction of the publicly funded qHPV vaccination program. Different sexual habits in adolescents are, at most, responsible for a small portion of the reduction in AGW incidence.

The impact of pertussis vaccine programme changes on pertussis disease burden in Manitoba, 1992-2017-an age-period-cohort analysis.

BACKGROUND: Changes to pertussis vaccination programmes can have impacts on disease burden that should be estimated independently from factors such as age- and period-related trends. We used age-period-cohort (APC) models to explore pertussis incidence in Manitoba over a 25-year period (1992-2017). METHODS: We identified all laboratory-confirmed cases of pertussis from Manitoba's Communicable Diseases Database and calculated age-standardized incidence rates. We used APC models to investigate trends in pertussis incidence. RESULTS: During the study period, 2479 cases were reported. Age-standardized rates were highest during a large outbreak in 1994 (55 cases/100 000 person-years), with much lower peaks in 1998, 2012 and 2016. We saw strong age and cohort effects in the APC models, with a steady decrease in incidence with increasing age and increased risk in the cohort born between 1980 and 1995. CONCLUSIONS: The highest risk for pertussis was consistently in young children, regardless of birth cohort or time period. The 1981 programme change to an adsorbed whole-cell pertussis vaccine with low effectiveness resulted in reduced protection in the 1981-95 birth cohort and contributed to the largest outbreak of disease during the 25-year study period.

Background incidence rates of hospitalisations and emergency department visits for thromboembolic and coagulation disorders in Ontario, Canada for COVID-19 vaccine safety assessment: a population-based retrospective observational study.

OBJECTIVE: The objective of this study was to estimate background rates of selected thromboembolic and coagulation disorders in Ontario, Canada. DESIGN: Population-based retrospective observational study using linked health administrative databases. Records of hospitalisations and emergency department visits were searched to identify cases using International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada diagnostic codes. PARTICIPANTS: All Ontario residents. PRIMARY OUTCOME MEASURES: Incidence rates of ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, deep vein thrombosis, pulmonary embolism, idiopathic thrombocytopaenia, disseminated intravascular coagulation and cerebral venous thrombosis during five prepandemic years (2015-2019) and 2020. RESULTS: The average annual population was 14 million with 51% female. The mean annual rates per 100 000 population during 2015-2019 were 127.1 (95% CI 126.2 to 127.9) for ischaemic stroke, 22.0 (95% CI 21.6 to 22.3) for intracerebral haemorrhage, 9.4 (95% CI 9.2 to 9.7) for subarachnoid haemorrhage, 86.8 (95% CI 86.1 to 87.5) for deep vein thrombosis, 63.7 (95% CI 63.1 to 64.3) for pulmonary embolism, 6.1 (95% CI 5.9 to 6.3) for idiopathic thrombocytopaenia, 1.6 (95% CI 1.5 to 1.7) for disseminated intravascular coagulation, and 1.5 (95% CI 1.4 to 1.6) for cerebral venous thrombosis. Rates were lower in 2020 than during the prepandemic years for ischaemic stroke, deep vein thrombosis and idiopathic thrombocytopaenia. Rates were generally consistent over time, except for pulmonary embolism, which increased from 57.1 to 68.5 per 100 000 between 2015 and 2019. Rates were higher for females than males for subarachnoid haemorrhage, pulmonary embolism and cerebral venous thrombosis, and vice versa for ischaemic stroke and intracerebral haemorrhage. Rates increased with age for most of these conditions, but idiopathic thrombocytopaenia demonstrated a bimodal distribution with incidence peaks at 0-19 years and ≥60 years. CONCLUSIONS: Our estimated background rates help contextualise observed events of these potential adverse events of special interest and to detect potential safety signals related to COVID-19 vaccines.

Patterns and descriptors of COVID-19 testing and lab-confirmed COVID-19 incidence in Manitoba, Canada, March 2020-May 2021: A population-based study.

BACKGROUND: We studied lab-confirmed COVID-19 infection (LCCI) testing, incidence, and severity. METHODS: We included all Manitoba residents and limited our severity analysis to LCCI patients. We calculated testing, incidence and vaccination rates between March 8, 2020 and June 1, 2021. We estimated the association between patient characteristics and testing (rate ratio [RR]; Poisson regression), including the reason for testing (screening, symptomatic, contact/outbreak asymptomatic), incidence (hazard ratio [HR]; Cox regression), and severity (prevalence ratio [PR], Cox regression). FINDINGS: The overall testing rate during the second/third wave was 570/1,000 person-years, with an LCCI rate of 50/1,000 person-years. The secondary attack rate during the second/third wave was 16%. Across regions, young children (<10) had the lowest positivity for symptomatic testing, the highest positivity for asymptomatic testing, and the highest risk of LCCI as asymptomatic contact. People in the lowest income quintile had the highest risk of LCCI, 1.3-6x the hazard of those in the highest income quintile. Long-term care (LTC) residents were particularly affected in the second wave with HRs>10 for asymptomatic residents. INTERPRETATION: Although the severity of LCCI in children was low, they have a high risk of asymptomatic positivity. The groups most vulnerable to LCCI, who should remain a focus of public health, were residents of Manitoba's North, LTC facilities, and low-income neighbourhoods. FUNDING: Canada Research Chair Program.

Effectiveness of BNT162b2 and mRNA-1273 covid-19 vaccines against symptomatic SARS-CoV-2 infection and severe covid-19 outcomes in Ontario, Canada: test negative design study.

OBJECTIVE: To estimate the effectiveness of mRNA covid-19 vaccines against symptomatic infection and severe outcomes (hospital admission or death). DESIGN: Test negative design study. SETTING: Ontario, Canada between 14 December 2020 and 19 April 2021. PARTICIPANTS: 324 033 community dwelling people aged ≥16 years who had symptoms of covid-19 and were tested for SARS-CoV-2. INTERVENTIONS: BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine. MAIN OUTCOME MEASURES: Laboratory confirmed SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR) and hospital admissions and deaths associated with SARS-CoV-2 infection. Multivariable logistic regression was adjusted for personal and clinical characteristics associated with SARS-CoV-2 and vaccine receipt to estimate vaccine effectiveness against symptomatic infection and severe outcomes. RESULTS: Of 324 033 people with symptoms, 53 270 (16.4%) were positive for SARS-CoV-2 and 21 272 (6.6%) received at least one dose of vaccine. Among participants who tested positive, 2479 (4.7%) were admitted to hospital or died. Vaccine effectiveness against symptomatic infection observed ≥14 days after one dose was 60% (95% confidence interval 57% to 64%), increasing from 48% (41% to 54%) at 14-20 days after one dose to 71% (63% to 78%) at 35-41 days. Vaccine effectiveness observed ≥7 days after two doses was 91% (89% to 93%). Vaccine effectiveness against hospital admission or death observed ≥14 days after one dose was 70% (60% to 77%), increasing from 62% (44% to 75%) at 14-20 days to 91% (73% to 97%) at ≥35 days, whereas vaccine effectiveness observed ≥7 days after two doses was 98% (88% to 100%). For adults aged ≥70 years, vaccine effectiveness estimates were observed to be lower for intervals shortly after one dose but were comparable to those for younger people for all intervals after 28 days. After two doses, high vaccine effectiveness was observed against variants with the E484K mutation. CONCLUSIONS: Two doses of mRNA covid-19 vaccines were observed to be highly effective against symptomatic infection and severe outcomes. Vaccine effectiveness of one dose was observed to be lower, particularly for older adults shortly after the first dose.

Pertussis vaccine effectiveness and duration of protection - A systematic review and meta-analysis.

A comprehensive review of observational pertussis vaccine effectiveness (VE) studies is needed to update gaps from previous reviews. We conducted a systematic review of VE and duration of protection studies for the whole-cell (wP) and acellular (aP) pertussis vaccines and conducted a formal meta-analysis using random effects models. Evidence continues to suggest that receipt of any pertussis vaccine confers protection in the short-term against disease although this protection wanes rapidly for aP vaccine. We detected significant heterogeneity in pooled estimates due, in part, to factors such as bias and confounding which may be mitigated by study design. Our review of possible sources of heterogeneity may help interpretation of other VE studies and aid design decisions in future pertussis VE research.