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Background: Vaccination of pregnant people with a vaccine containing acellular pertussis (tetanus–diphtheria–acellular pertussis [Tdap]) has been recommended in Canada since 2018, and the evaluation of delivery models for efficient maternal Tdap administration is a priority for the Quebec Ministry of Health. We implemented 3 vaccine delivery models, in addition to the existing standard of practice model, and compared the vaccine coverage achieved by the 4 models in Quebec. Methods: In this quasiexperimental, multicentre observational study, we recruited pregnant people at less than 21 weeks’ gestation in 4 Quebec regions from April to October 2019. We compared 4 vaccine delivery models: local community service centres (centre local de services communautaires [CLSCs], baseline), family medicine groups (FMGs), obstetrics clinic and the oral glucose challenge test (OGCT). In addition to the CLSCs, 3 FMGs, 1 obstetric clinic and a hospital-based OGCT screening program participated. We determined vaccination status from a self-reported questionnaire, the Quebec Immunization Registry or medical charts. We compared model-specific (for participants recruited to a model and subsequently vaccinated within that model) and overall vaccine coverage (considering all vaccine delivery pathways) and used logistic regression to adjust for sociodemographic variables. Results: Overall, 946 of 1000 recruited pregnant people were eligible for analyses. Vaccination via the FMGs achieved the highest model-specific vaccine coverage (67.8%, 95% confidence interval [CI] 60.5%–74.4%), but coverage was not significantly different from the CLSCs (63.8%, 95% CI 57.6%–69.6%). For overall vaccine coverage, the FMG (86.5%, 95% CI 80.6%–90.9%) and obstetrics models (85.9%, 95% CI 80.9%–89.7%) achieved significantly higher vaccine coverage than the CLSCs (66.3%, 95% CI 60.1%–71.9%). The OGCT model did not improve overall vaccine coverage (61.8%, 95% CI 56.1%–67.2%). Interpretation: Compared with CLSCs, overall vaccine coverage was higher when Tdap was offered in FMGs or an obstetrics clinic providing prenatal care. Health professionals involved in pregnancy follow-up recommending and offering the vaccine may be a key factor in optimizing vaccine coverage.

Background The success of current and prospective COVID-19 vaccine campaigns for children and adolescents will in part depend on the willingness of parents to accept vaccination. This study examined social determinants of parental COVID-19 vaccine acceptance and uptake for children and adolescents. Methods We used cross-sectional data from an ongoing COVID-19 cohort study in Montreal, Canada and included all parents of 2 to 18-year-olds who completed an online questionnaire between May 18 and June 26, 2021 (n = 809). We calculated child age-adjusted prevalence estimates of vaccine acceptance by parental education, race/ethnicity, birthplace, household income, and neighbourhood, and used multinomial logistic regression to estimate adjusted prevalence differences (aPD) and ratios (aPR). Social determinants of vaccine uptake were examined for the vaccine-eligible sample of 12 to 18 year-olds (n = 306). Results Intention to vaccinate children against COVID-19 was high, with only 12.4% of parents unlikely to have their child vaccinated. Parents with younger children were less likely to accept vaccination, as were those from lower-income households, racialized groups, and those born outside Canada. Children from households with annual incomes

Background Sink drains are known reservoirs of pathogens and have been associated with multiple nosocomial outbreaks. In this study, the distribution of Serratia marcescens was investigated within the sink environment of a NICU and in colonized or infected newborns. The effect of different types of drain disinfection on bacterial concentration and on the detection of Serratia marcescens in sink drains was also investigated. Methods Sink drains from a NICU were sampled: 20 drains sampled for 6 weeks in the first year and 28 drains sampled for 5 months in the second year. S. marcescens isolated from positive patients were collected. A high-throughput short sequence typing (HiSST) method was developed to identify S. marcescens and compare strains and environmental DNA from sink drains with 56 clinical strains from 5 nosocomial outbreaks. Five interventions were tested: self-disinfecting drains, hot water disinfection, chlorine disinfection, steam disinfection and hot tap water flushing. Bacterial concentration of samples was measured in culture and flow cytometry and the HiSST method was used to identify S. marcescens. Results During the first and second sampling campaigns, 40% and 60% of sink drain samples were positive for S. marcescens with a moderate genotype diversity (1 to 11 different STs). The genotype profile of the 56 clinical strains was heterogeneous (26 STs). Four distinct STs were retrieved in 8 sinks after detection in patients whereas 1 ST was detected in a sink before detection in patient. Some environmental and clinical strains were found in drains for up to a year after the first sampling campaign. Each tested drain intervention reduced culturable bacteria (4-8 log) and viable bacteria (2-3 log), except for chlorine. The self-disinfecting drains, hot water and steam disinfection were able to remove temporarily S. marcescens from the drains. Conclusion The high genotypic diversity of the clinical strains suggests diffuse sources of S. marcescens within the NICU likely to cause nosocomial infection outbreaks. The self-disinfecting drains, hot water and steam disinfection seem to be the best methods to reduce bacterial concentration in drains and eliminate S. marcescens in the short term, thus limiting the risk of pathogens spread from the sink environment to patients. Disclosures All Authors: No reported disclosures.

ImportanceRepeated serological testing for SARS-CoV-2 allows the monitoring of antibody dynamics in populations, including detecting infections that are missed by RT-PCR or antigen testing. Understanding the factors associated with seroconversion and seroreversion as well as the duration of infection-induced antibodies can also inform public health recommendations regarding disease prevention and mitigation efforts.ObjectiveTo use serological testing to assess the prevalence, seroconversion, and seroreversion of infection-induced SARS-CoV-2 antibodies in children and adolescents in Montreal, Canada.DesignThis analysis reports on three rounds of data collection from a prospective cohort study (Enfants et COVID-19: Étude de séroprévalence [EnCORE]). The study rounds occurred as follows: Round 1 October 2020-March 2021, Round 2 May to July 2021, and Round 3 November 2021 to January 2022. Most Round 3 samples were collected prior to the spread of the Omicron BA.1 variant in Quebec.SettingPopulation-based sample.ParticipantsChildren and adolescents aged 2 to 17 years in Montreal, Canada.ExposurePotential exposure to SARS-CoV-2.Main Outcomes and MeasuresParticipants provided dried blood spots (DBS) for antibody detection and parents completed online questionnaires for sociodemographics and COVID-19 symptoms and testing history. The serostatus of participants was determined by enzyme-linked immunosorbent assays (ELISAs) using the receptor-binding domain (RBD) from the spike protein and the nucleocapsid protein (N) as antigens. We estimated seroprevalence for each round of data collection and by participant and household characteristics. Seroconversion rates were calculated as were the likelihoods of remaining seropositive at six months and one year.ResultsThe study included DBS samples from 1 632, 936, and 723 participants in the first, second, and third rounds of data collection, respectively. The baseline seroprevalence was 5·8% (95% CI 4·8-7·1), which increased to 10·5% and 10·9% for the respective follow-ups (95% CI 8·6-12·7; 95% CI 8·8-13·5). The overall average crude rate of seroconversion over the study period was 12·7 per 100 person-years (95% CI 10·9-14·5). Adjusted hazard rates of seroconversion by child and household characteristics showed higher rates in children who were female, whose parent identified as a racial or ethnic minority, and in households with incomes less than 100K. The likelihood of remaining seropositive at six months was 67% (95% CI 59-76) and dropped to 19% (95% CI 11%-33%) at one year.Conclusions and RelevanceThe data reported here provide estimates of pre-Omicron seroprevalence, seroconversion rates and time to seroreversion in a population-based cohort of children and adolescents. Serological studies continue to provide valuable contributions for infection prevalence estimates and help us better understand the dynamics of antibody levels following infection. Continued study of seroconversion and seroreversion can inform public health recommendations such as COVID-19 vaccination and booster schedules.KEY POINTSQuestionWhat was the rate of seroconversion and time to seroreversion for SARS-CoV-2 antibodies among children and adolescents in Montreal between October 2020 to January 2022?FindingsThe overall average crude rate of seroconversion was 12·7 per 100 person-years (95% CI 10·9-14·5). We observed higher rates of seroconversion in children who were female, whose parent identified as a racial or ethnic minority, and in households with incomes less than 100K. Among all children who seroconverted, 71% had not been previously diagnosed with COVID-19. Median time to seroreversion was 7·5 months.MeaningEven before the emergence of the Omicron variants, we observed a high rate of seroconversion for infection-induced SARS-CoV-2 antibodies along with widespread antibody waning by one year. Many children and adolescents seroconverted despite not receiving a prior COVID-19 diagnosis, indicating that RT-PCR and antigen testing continue to underestimate true disease prevalence.

Objective To describe variables used by Saudi pediatric intensivists to make antibiotic-related decisions for children with suspected severe bacterial infections. Methods We conducted a cross-sectional survey, which was developed using a multi-step methodological approach. The survey included 4 clinical scenarios of the most relevant bacterial infections in pediatric critical care (pneumonia, sepsis, meningitis and intra-abdominal infection). The potential determinants of antibiotic treatment duration addressed in all scenarios included clinical variables (patient characteristics, disease severity), laboratory infection markers, radiologic findings, and pathogens. Results The response rate was 65% (55/85). Eight variables (immunodeficiency, 3 months of age, 2 or more organ dysfunctions, Pediatric Risk of Mortality III score >10, leukocytosis, elevated C-reactive protein [CRP], elevated erythrocyte sedimentation rate [ESR], and elevated procalcitonin [PCT]) were associated with prolonging antibiotic treatment duration for all 4 clinical scenarios, with a median increase ranging from 3.0 days (95% confidence interval [CI] 0.5, 3.5, leukocytosis) to 8.8 days (95% CI 5.5, 10.5, immunodeficiency). There were no variables that were consistently associated with shortening antibiotic duration across all scenarios. Lastly, the proportion of physicians who would continue antibiotics for ≥5 days despite a positive viral polymerase chain reaction test result was 67% for pneumonia, 85% for sepsis, 63% for meningitis, and 95% for intra-abdominal infections. Conclusion Antibiotic-related decisions for critically ill patients are complex and depend on several factors. Saudi pediatric intensivists will use prolonged courses of antibiotics for younger patients, patients with severe clinical picture, and patients with persistently elevated laboratory markers and hospital acquired infections, even when current literature and guidelines do not suggest such practices. Antimicrobial stewardship programs should include interventions to address these misconceptions to ensure the rational use of antibiotics in pediatric intensive care units.

On March 3, 2021, faced with ongoing morbidity and mortality from coronavirus disease 2019 (COVID-19) and insufficient supplies of authorized, available vaccines against COVID-19 in Canada, the National Advisory Committee on Immunization (NACI) issued a strong recommendation to allow for an extended interval between vaccine doses to maximize the number of people protected as quickly as possible. NACI's recommendation was released in the form of a rapid response because of the urgency of the situation and was based on a review of the evidence; principles of immunology; historical experience with vaccines; modelling studies; and consideration of ethics, equity, feasibility, and acceptability. Since then, many questions and concerns have been raised. This article aims to provide further explanation of the rationale for the decision and prepare health care providers with information they need as they support their patients in the vaccination rollout.Le 3 mars 2021, devant la morbidité et la mortalité continues causées par la maladie à coronavirus 2019 (COVID-19) et l’offre insuffisante de vaccins autorisés et disponibles contre la COVID-19 au Canada, le Comité consultatif national de l’immunisation a publié une forte recommandation préconisant un intervalle prolongé entre les doses des vaccins, afin d’optimiser le nombre de personnes protégées le plus rapidement possible. La recommandation du comité, qui a pris la forme d’une réponse rapide en raison de l’urgence de la situation, repose sur l’examen des données probantes, les principes immunologiques, l’expérience des vaccins, les études de modélisation et les principes d’éthique, d’équité, de faisabilité et d’acceptabilité. De nombreuses questions et inquiétudes ont été soulevées depuis. Le présent article vise à mieux expliquer les motifs de cette recommandation et à fournir aux dispensateurs de soins l’information dont ils ont besoin pour soutenir leurs patients pendant le déploiement de la vaccination.

Le 3 mars 2021, devant la morbidité et la mortalité continues causées par la maladie à coronavirus 2019 (COVID-19) et l’offre insuffisante de vaccins autorisés et disponibles contre la COVID-19 au Canada, le Comité consultatif national de l’immunisation a publié une forte recommandation préconisant un intervalle prolongé entre les doses des vaccins, afin d’optimiser le nombre de personnes protégées le plus rapidement possible. La recommandation du comité, qui a pris la forme d’une réponse rapide en raison de l’urgence de la situation, repose sur l’examen des données probantes, les principes immunologiques, l’expérience des vaccins, les études de modélisation et les principes d’éthique, d’équité, de faisabilité et d’acceptabilité. De nombreuses questions et inquiétudes ont été soulevées depuis. Le présent article vise à mieux expliquer les motifs de cette recommandation et à fournir aux dispensateurs de soins l’information dont ils ont besoin pour soutenir leurs patients pendant le déploiement de la vaccination.

The effect of the COVID-19 pandemic on maternal mental health has been described in Canada and China but no study has compared the two countries using the same standardized and validated instruments. In this study, we aimed to evaluate and compare the impact of COVID-19 public health policies on maternal mental health between Canada and China, as we hypothesize that geographical factors and different COVID-19 policies are likely to influence maternal mental health. Pregnant persons >18 years old were recruited in Canada and China using a web-based strategy. All participants recruited between 26 June 2020 and 16 February 2021 were analyzed. Self-reported data included sociodemographic variables, COVID-19 experience and maternal mental health assessments (Edinburgh Perinatal Depression Scale (EPDS), Generalized Anxiety Disorders (GAD-7) scale, stress and satisfaction with life). Analyses were stratified by recruitment cohort, namely: Canada 1 (26 June 2020–10 October 2020), Canada 2 and China (11 October 2020–16 February 2021). Overall, 2423 participants were recruited, with 1804 participants within Canada 1, 135 within Canada 2 and 484 in China. The mean EDPS scores were 8.1 (SD, 5.1) in Canada 1, 8.1 (SD, 5.2) in Canada 2 and 7.7 (SD, 4.9) in China (p-value Canada 2/China: p = 0.005). The mean GAD-7 scores were 2.6 (SD, 2.9) in China, 4.3 (SD, 3.8) in Canada 1 (p < 0.001) and 5.8 (SD, 5.2) in Canada 2 (p < 0.001). When adjusting for stress and anxiety, being part of the Chinese cohort significantly increased the chances of having maternal depression by over threefold (adjusted OR 3.20, 95%CI 1.77–5.78). Canadian and Chinese participants reported depressive scores nearly double those of other crises and non-pandemic periods. Lockdowns and reopening periods have an important impact on levels of depression and anxiety among pregnant persons.

In Quebec, antibiotic use is higher among outpatients with chronic diseases. We sought to measure compliance with provincial guidelines for the treatment of otitis media and common respiratory infections, and to measure variations in compliance according to the presence of certain chronic diseases.We conducted a population-based study of linked data on antibiotic dispensing covered by the public drug insurance plan between April 2010 and March 2017. We included patients who had consulted a primary care physician within 2 days before being dispensed an antibiotic for an infection targeted by provincial guidelines, including bronchitis in patients with chronic obstructive pulmonary disease, otitis media, pharyngitis, pneumonia and sinusitis. We computed proportions of prescriptions compliant with guidelines (use of recommended antibiotic for children, and use of recommended antibiotic and dosage for adults) by age group (children or adults) and chronic disease (respiratory, cardiovascular, diabetes, mental disorder or none). We measured the impact of chronic diseases on compliance using robust Poisson regression.We analyzed between 14 677 and 198 902 prescriptions for each infection under study. Compliance was greater than 87% among children, but was lower among children with asthma (proportion ratios between 0.97 and 1.00). In adults, the chosen antibiotic was compliant for at least 73% of prescriptions, except for pharyngitis (≤ 61%). Accounting for dosage lowered compliance to between 31% and 61%. Compliance was lower in the presence of chronic diseases (proportion ratios between 0.94 and 0.98).It is possible that prescribing noncompliant prescriptions was sometimes appropriate, but the high frequency of noncompliance suggests room for improvement. Given that variations associated with chronic diseases were small, disease-specific guidelines for antibiotic prescriptions are likely to have a limited impact on compliance.

Background The study objectives were to ascertain the efficacy of vitamin D supplementation in rapidly increasing serum vitamin D and of implementation of a hybrid (virtual and in-person) trial. Methods In a randomised triple-blind controlled trial, healthcare workers were allocated to receive an oral bolus of 100,000 IU with 10,000 IU/week vitamin D3 or placebo. The co-primary outcomes of this ancillary study were the change from baseline in serum 25-hydroxyvitamin D [(Δ) 25(OH)D] and proportion with vitamin D sufficiency (25(OH)D ≥ 75nmol/L), at endpoint. Adherence to supplements and procedures as well as adverse event rates were documented. Results Thirty-four (19 intervention, 15 control) subjects were randomised, with 28 (41%) virtual visits. After 44.78 ± 11.00 days from baseline, a significant adjusted group difference of 44.2 (34.7, 53.8) nmol/L was observed in the Δ 25(OH)D (95%CI) in favor of supplementation; 77.8% of intervention, and 13.3% of control, patients were vitamin D sufficient (OR:6.11, 95%CI:1.6, 22.9). The adherence to intervention was 94.7% in the intervention and 100% in the control groups. Irrespective of visit type, high adherence was observed in sampling procedures and completion of fortnightly online questionnaire. No adverse events attributable to vitamin D were reported. Conclusion The vitamin D supplementation rapidly and safely raised 25(OH)D levels to sufficient levels for a biological effect. Similarly high adherence to study procedures was observed with virtual and in-person participation. Trial registration: This trial was registered at https://clinicaltrials.gov on July 23, 2020 (#NCT04483635)

IntroductionIn the COVID-19 pandemic, healthcare workers (HCWs) were at high risk of infection due to their exposure to COVID infections. HCWs were the backbone of our healthcare response to this pandemic; every HCW withdrawn or lost due to infection had a substantial impact on our capacity to deliver care. Primary prevention was a key approach to reduce infection. Vitamin D insufficiency is highly prevalent in Canadians and worldwide. Vitamin D supplementation has been shown to significantly decrease the risk of respiratory infections. Whether this risk reduction would apply to COVID-19 infections remained to be determined. This study aimed to determine the impact of high-dose vitamin D supplementation on incidence of laboratory-confirmed COVID-19 infection rate and severity in HCWs working in high COVID incidence areas.Methods and analysisPROTECT was a triple-blind, placebo-controlled, parallel-group multicentre trial of vitamin D supplementation in HCWs. Participants were randomly allocated in a 1:1 ratio in variable block size to intervention (one oral loading dose of 100 000 IU vitamin D3+10 000 IU weekly vitamin D3) or control (identical placebo loading dose+weekly placebo). The primary outcome was the incidence of laboratory-confirmed COVID-19 infection, documented by RT-qPCR on salivary (or nasopharyngeal) specimens obtained for screening or diagnostic purposes, as well as self-obtained salivary specimens and COVID-19 seroconversion at endpoint. Secondary outcomes included disease severity; duration of COVID-19-related symptoms; COVID-19 seroconversion documented at endpoint; duration of work absenteeism; duration of unemployment support; and adverse health events. The trial was terminated prematurely, due to recruitment difficulty.Ethics and disseminationThis study involves human participants and was approved by the Research Ethics Board (REB) of the Centre hospitalier universitaire (CHU) Sainte-Justine serving as central committee for participating institutions (#MP-21-2021-3044). Participants provided written informed consent to participate in the study before taking part. Results are being disseminated to the medical community via national/international conferences and publications in peer-reviewed journals.Trial registration numberhttps://clinicaltrials.gov/ct2/show/NCT04483635.

BACKGROUND In North America, the first dose of a measles-containing vaccine (MCV1) is administered at ≥12 months of age. However, MCV1 may be given to infants

Canadian long-term care facility (LTCF) residents experienced higher death rates compared to other countries during the first wave of the COVID-19 pandemic. This cohort study analyzes the individual, therapeutic, and institutional factors associated with death in LTCFs.Institutional data for 17 LTCFs in Montreal, Canada were obtained from local administrative registries. Individual data for 1197 residents infected by SARS-CoV-2 between February 23 and July 11, 2020 were obtained through chart reviews. A multivariable modified Poisson regression model, which accounted for LTCF clustering, was used to identify resident and facility covariates associated with 30-day mortality after COVID-19 diagnosis.Severe shortage of licensed practical nurses (RR 2.60 95% CI 1.20-5.61) and medium-sized facilities compared to smaller-sized facilities (RR 2.73 95% CI 1.23-6.07) were associated with 30-day mortality. Later COVID-19 diagnosis (RR 0.98 95% CI 0.97-0.99 per additional day) was associated with survival. Individual risk factors for death included age (RR 1.33 95% CI 1.23-1.45 per additional 10 years), male sex (RR 1.46 95% CI 1.24-1.71), functional impairment (RR 1.08 95% CI 1.04-1.12 per unit increase of SMAF), as well as a diagnosis of congestive heart failure (RR 1.31 95% CI 1.04-1.66) and neurocognitive disorder (RR 1.31 95% CI 1.01-1.70). Among severe cases, anticoagulation was associated with survival (RR 0.70 95% CI 0.51-0.96).This study identified practical nurse shortages and facility size as institutional risk factors for COVID-19 death. Anticoagulation was associated with survival among severe cases.

Understanding the immune response to natural infection by SARS-CoV-2 is key to pandemic management, especially in the current context of emerging variants. Uncertainty remains regarding the efficacy and duration of natural immunity against reinfection.We conducted an observational prospective cohort study in Canadian healthcare workers (HCWs) with a history of PCR-confirmed SARS-CoV-2 infection to (i) measure the average incidence rate of reinfection and (ii) describe the serological immune response to the primary infection.Our cohort comprised 569 HCWs; median duration of individual follow-up was 371 days. We detected six cases of reinfection in absence of vaccination between August 21, 2020, and March 1, 2022, for a reinfection incidence rate of 4.0 per 100 person-years. Median duration of seropositivity was 415 days in symptomatics at primary infection compared with 213 days in asymptomatics (p 0.0001). Other characteristics associated with prolonged seropositivity for IgG against the spike protein included age over 55 years, obesity, and non-Caucasian ethnicity.Among unvaccinated healthcare workers, reinfection with SARS-CoV-2 following a primary infection remained rare.

Background In Canada, vaccination against pertussis (Tdap) during pregnancy has been recommended since 2018, with suboptimal uptake. We aimed to assess the determinants of intention and uptake of Tdap vaccine among pregnant women in Quebec. Methods Participants ( 35 weeks). One measured vaccination intention and the other assessed the actual decision. Questionnaires were informed by the Theory of Planned Behaviour (TPB). We used logistic multivariate analysis to identify determinants of Tdap vaccination uptake during pregnancy using responses to both questionnaires. Results A total of 741 women answered the first survey and 568 (76.7%), the second survey. In the first survey most participants intended to receive the Tdap vaccine during their pregnancy (76.3%) and in the second survey, 82.4% reported having been vaccinated against Tdap during their pregnancy. In multivariate analysis, the main determinants of vaccine uptake were: a recommendation from a healthcare provider (OR = 7.6), vaccine intention (OR = 6.12), social norms (or thinking that most pregnant women will be vaccinated (OR = 3.81), recruitment site (OR = 3.61 for General Family Medicine unit) perceived behavioral control (or low perceived barriers to access vaccination services, (OR = 2.32) and anticipated feeling of guilt if not vaccinated (OR = 2.13). Safety concerns were the main reason for not intending or not receiving the vaccine during pregnancy. Conclusion We observed high vaccine acceptance and uptake of pertussis vaccine in pregnancy. The core components of the TPB (intention, social norms and perceived behavioral control) were all predictors of vaccine uptake, but our multivariate analysis also showed that other determinants were influential: being sufficiently informed about Tdap vaccination, not having vaccine safety concerns, and anticipated regret if unvaccinated. To ensure high vaccine acceptance and uptake in pregnancy, strong recommendations by trusted healthcare providers and ease of access to vaccination services remain instrumental.

IntroductionTo successfully combat COVID-19 vaccine hesitancy and increase uptake, research has demonstrated that interventions are most effective when tailored to meet local needs through active engagement and co-development with communities. This mixed-methods project uses a human-centred design (HCD) approach to understand local perspectives of COVID-19 vaccine hesitancy and develop strategies to enhance vaccine confidence for children and adolescents.Methods and analysisProject ECHO (Étude Communautaire sur l’Hésitation vaccinale contre la COVID-19) combines population-based surveys of parents and adolescents with community-based participatory action research to design and pilot strategies to enhance COVID-19 vaccine confidence in two underserved and ethnoculturally diverse neighbourhoods of Montreal, Canada. Two surveys conducted 6 months apart through primary and secondary schools are used to monitor vaccine acceptance and its social determinants among children and youth. Analyses of survey data include descriptive and inferential statistical approaches. Community-led design teams of parents and youth from the two participating neighbourhoods, supported by academic researchers, design thinking experts and community partners, use an HCD approach to: (1) gather data to understand COVID-19 vaccine decision-making among parents and youth in their community and frame a design challenge (inspiration phase); (2) develop an intervention to address the design challenge (ideation phase) and (3) pilot the intervention (implementation phase). Strategies to evaluate the community-led interventions will be co-developed during the implementation phase.Ethics and disseminationThis study has been approved by the research ethics boards of the Sainte-Justine University Hospital Centre and the University of Montreal. Community design teams will be involved in the dissemination of findings and the design of knowledge translation initiatives that foster dialogue related to COVID-19 vaccination for children and adolescents among community, school and public health stakeholders. Findings will be disseminated through peer-reviewed publications, conference presentations, community forums, policy briefs, and social media content.

ImportancePublic health vaccination recommendations for COVID-19 primary series and boosters in previously infected individuals differ worldwide. As infection with SARS-CoV-2 is often asymptomatic, it remains to be determined if vaccine immunogenicity is comparable in all previously infected subjects. We present detailed immunological evidence to clarify the requirements for one-or two-dose primary vaccination series for naturally primed individuals.ObjectiveEvaluate the immune response to COVID-19 mRNA vaccines in healthcare workers (HCWs) who recovered from a SARS-CoV-2 infection.DesignMulticentric observational prospective cohort study of HCWs with a PCR-confirmed SARS-CoV-2 infection designed to evaluate the dynamics of T and B cells immune responses to primary infection and COVID-19 mRNA vaccination over 12 months.ParticipantsUnvaccinated HCWs with PCR-confirmed SARS-CoV-2 infection were selected based on the presence or absence of symptoms at infection and serostatus at enrollment. Age- and sex-matched adults not infected with SARS-CoV-2 prior to vaccination were included as naïve controls.ExposureVaccination with Pfizer BioNTech BNT162b2 mRNA vaccine.Main Outcome(s) and Measure(s)Immunity score (zero to three), before and after vaccination, based on anti-RBD IgG ratio, serum capacity to neutralize live virus and IFN-γ secretion capacity in response to SARS-CoV-2 peptide pools above the positivity threshold for each of the three assays. We compared the immunity score between groups based on subjects’ symptoms at diagnosis and/or serostatus prior to vaccination.ResultsNone of the naïve participants (n=14) showed a maximal immunity score of three following one dose of vaccine compared to 84% of the previously infected participants (n=55). All recovered individuals who did not have an immunity score of three were seronegative prior to vaccination, and 67% had not reported symptoms resulting from their initial infection. Following one dose of vaccine, their immune responses were comparable to naïve individuals, with significantly weaker responses than those who were symptomatic during infection.Conclusions and RelevanceIndividuals who did not develop symptoms during their initial SARS-CoV-2 infection and were seronegative prior to vaccination present immune responses comparable to that of naïve individuals. These findings highlight the importance of administering the complete two-dose primary regimen and following boosters of mRNA vaccines to individuals who experienced asymptomatic SARS-CoV-2 infection.KEY POINTSQuestionIs a single dose of COVID-19 mRNA vaccine sufficient to induce robust immune responses in individuals with prior SARS-CoV-2 infection?FindingsIn this cohort of 55 health care workers previously infected with SARS-CoV-2, we show that the absence of symptoms during initial infection and negative serostatus prior to vaccination predict the strength of immune responses to COVID-19 mRNA vaccine. Lack of symptoms and a negative serostatus prior to vaccination leads to immune responses comparable to naïve individuals.MeaningOur results support a two-dose primary series requirement for any individual with prior history of asymptomatic SARS-CoV-2 infection.

Background: The COVID-19 pandemic has disproportionately affected health care workers. We sought to estimate SARS-CoV-2 seroprevalence among hospital health care workers in Quebec, Canada, after the first wave of the pandemic and to explore factors associated with SARS-CoV-2 seropositivity. Methods: Between July 6 and Sept. 24, 2020, we enrolled health care workers from 10 hospitals, including 8 from a region with a high incidence of COVID-19 (the Montréal area) and 2 from low-incidence regions of Quebec. Eligible health care workers were physicians, nurses, orderlies and cleaning staff working in 4 types of care units (emergency department, intensive care unit, COVID-19 inpatient unit and non-COVID-19 inpatient unit). Participants completed a questionnaire and underwent SARS-CoV-2 serology testing. We identified factors independently associated with higher seroprevalence. Results: Among 2056 enrolled health care workers, 241 (11.7%) had positive SARS-CoV-2 serology. Of these, 171 (71.0%) had been previously diagnosed with COVID-19. Seroprevalence varied among hospitals, from 2.4% to 3.7% in low-incidence regions to 17.9% to 32.0% in hospitals with outbreaks involving 5 or more health care workers. Higher seroprevalence was associated with working in a hospital where outbreaks occurred (adjusted prevalence ratio 4.16, 95% confidence interval [CI] 2.63–6.57), being a nurse or nursing assistant (adjusted prevalence ratio 1.34, 95% CI 1.03–1.74) or an orderly (adjusted prevalence ratio 1.49, 95% CI 1.12–1.97), and Black or Hispanic ethnicity (adjusted prevalence ratio 1.41, 95% CI 1.13–1.76). Lower seroprevalence was associated with working in the intensive care unit (adjusted prevalence ratio 0.47, 95% CI 0.30–0.71) or the emergency department (adjusted prevalence ratio 0.61, 95% CI 0.39–0.98). Interpretation: Health care workers in Quebec hospitals were at high risk of SARS-CoV-2 infection, particularly in outbreak settings. More work is needed to better understand SARS-CoV-2 transmission dynamics in health care settings.

Summary Background Many immigrants are susceptible to varicella on arrival to Canada because of different transmission dynamics in their countries of origin and scarcity of vaccination. Universal childhood vaccination programmes decrease varicella incidence rates through herd immunity, but the accumulating number of susceptible adult immigrants could remain at risk for severe varicella. Our aim was to describe the epidemiology of varicella among immigrants and non-immigrants before and after childhood varicella vaccination. Methods We did a population-based, retrospective cohort study of all varicella cases in Quebec, Canada, diagnosed between 1996 and 2014 in administrative health databases linked to immigration data. Cases of varicella met diagnostic codes in the International Classification of Diseases, Ninth and Tenth Revision Canadian modifications. Cases with a co-occurring zoster diagnostic code and immigrants from Australia, New Zealand, the USA, and western European countries were excluded. Vaccination periods included pre-vaccination (1996–98), private vaccination (1999–2005), and public vaccination (2006–14). Incidence rate and comparative rate ratios were estimated using census data. Findings A total of 231 339 varicella cases diagnosed between Jan 1, 1996, and Dec 31, 2014, were linked to 1 115 696 immigrants who arrived between Jan 1, 1980, and Dec 31, 2014. 1444 herpes zoster cases and 1276 immigrants from Australia, western Europe, New Zealand, and the USA were excluded. Among 228 619 varicella cases, 13 315 (5·8%) occurred in immigrants. In pre-vaccination versus public vaccination periods, varicella incidence declined in immigrants by 87% (95% CI 86·6–87·9; 324·3 cases per 100 000 person-years to 40·9 cases per 100 000 person-years) and in non-immigrants by 93% (92·4–92·7; 484 cases per 100 000 person-years to 36 cases per 100 000 person-years). Mean age at diagnosis increased in both groups (15·1 vs 19·4 years in immigrants and 8·4 vs 12·0 years in non-immigrants). In the public vaccination period, immigrants younger than 50 years had higher varicella rates than non-immigrants, with relative risk ranging from 1·53 (95% CI 1·37–1·72) to 4·64 (3·90–5·53) with the highest risk in adolescents and young adults, and people from Latin America and the Caribbean (age-specific incidence rate ratio [aIRR]I-NI pre-vaccination 2·19 and post-vaccination aIRRI-NI6·07) and south Asia (aIRRI-NI pre-vaccination 3·41 and aIRRI-NI post-vaccination 4·46) and in childbearing women (15–40 years; IRRI-NI 2·48). Interpretation Immigrant adolescents, young adults, and women of childbearing age had higher age-standardised rates of varicella than non-immigrants, with increasing disparities following vaccine introduction. Immigrants younger than 50 years of age would benefit from targeted vaccination upon arrival to host countries. Funding The Canadian Institutes of Health Research and The Department of Medicine, Jewish General Hospital, Montreal, QC, Canada.

This document is part of the “SHEA Neonatal Intensive Care Unit (NICU) White Paper Series.” It is intended to provide practical, expert opinion, and/or evidence-based answers to frequently asked questions about CLABSI detection and prevention in the NICU. This document serves as a companion to the CDC Healthcare Infection Control Practices Advisory Committee (HICPAC) Guideline for Prevention of Infections in Neonatal Intensive Care Unit Patients. Central line-associated bloodstream infections (CLABSIs) are among the most frequent invasive infections among infants in the NICU and contribute to substantial morbidity and mortality. Infants who survive CLABSIs have prolonged hospitalization resulting in increased healthcare costs and suffer greater comorbidities including worse neurodevelopmental and growth outcomes. A bundled approach to central line care practices in the NICU has reduced CLABSI rates, but challenges remain. This document was authored by pediatric infectious diseases specialists, neonatologists, advanced practice nurse practitioners, infection preventionists, members of the HICPAC guideline-writing panel, and members of the SHEA Pediatric Leadership Council. For the selected topic areas, the authors provide practical approaches in question-and-answer format, with answers based on consensus expert opinion within the context of the literature search conducted for the companion HICPAC document and supplemented by other published information retrieved by the authors. Two documents in the series precede this one: “Practical approaches to Clostridioides difficile prevention” published in August 2018 and “Practical approaches to Staphylococcus aureus prevention,” published in September 2020.

The World Health Organization (WHO) has declared that antimicrobial resistance is one of the top ten global public health threats humanity is facing. To tackle this problem, it is necessary to not only address it in the hospital setting, but even more so in the community. In this context, understanding people's knowledge, attitudes, and practices towards antimicrobial resistance is of utmost importance. Accordingly, we investigated whether students from the Université de Montréal (Quebec, Canada) had perceptions and behaviours that could foster bacterial resistance.We conducted an observational, cross-sectional, prospective, and descriptive study from November 30 to December 11, 2020. We applied an online questionnaire (Google Forms) adapted from the WHO survey entitled 'Antibiotic resistance: Multi-country public awareness survey.'Overall, 106 participants were included in this study. Most of them demonstrated reasonable understanding and behaviours related to antimicrobial resistance. Erroneous response proportions ranged from 0.9% to 25.5%, except for the statement 'Antibiotic resistance occurs when your body becomes resistant to antibiotics, and they no longer work,' where 63.2% of participants answered that it was true, even though it is false. Regarding antibiotic use, 28.3% of participants said they already had used antibiotics without a doctor's prescription. Of these, 55.2% were Canadian students.This study indicates a possible misuse of antimicrobials in an area where antibiotics should not be easily accessible without a prescription. It is necessary to investigate why these medications are being used without being prescribed. Furthermore, we demonstrate a need to increase public awareness to better understand antimicrobial resistance's theoretical basis.Selon l’Organisation mondiale de la Santé (OMS), la résistance antimicrobienne (RAM) est l’une des dix menaces sanitaires pour l’humanité. Pour faire face à ce problème, il est nécessaire de l’aborder non seulement dans le cadre hospitalier, mais encore davantage au sein de la communauté. Dans ce contexte, il est primordial de comprendre les connaissances, les attitudes et les pratiques de la population vis-à-vis de la résistance antimicrobienne. Ainsi, les chercheurs ont cherché à savoir si les perceptions et les comportements de la communauté étudiante de l’Université de Montréal (Québec, Canada) pouvaient contribuer à la propagation de la résistance bactérienne.Les chercheurs ont réalisé une étude observationnelle de type transversal, prospectif et descriptif entre le 30 novembre et le 11 décembre 2020. Ils ont utilisé un questionnaire en ligne (formulaires Google) adapté du sondage de l’OMS intituléAu total, 106 participants ont été inclus dans l’étude. La plupart ont démontré avoir une compréhension et des comportements raisonnables au sujet de la RAM. Les proportions de réponses erronées se situaient entre 0,9 % et 25,5 %, sauf pour la proposition « La résistance aux antibiotiques survient lorsque votre corps devient résistant aux antibiotiques et qu’ils ne fonctionnent plus », pour laquelle 63,2 % des participants ont répondu que c’était vrai, même si c’est faux. En ce qui concerne l’utilisation des antibiotiques, 28,3 % des participants ont déclaré avoir déjà utilisé des antibiotiques sans prescription médicale, et 55,2 % d’entre eux étaient des étudiants canadiens.La présente étude signale la possibilité que les antimicrobiens soient mal utilisés dans une région où les antibiotiques ne devraient pas être facilement accessibles sans prescription. Une étude s’impose pour savoir pourquoi ces médicaments sont utilisés sans être prescrits. De plus, les chercheurs démontrent la nécessité de sensibiliser le public aux fondements théoriques de la résistance antimicrobienne.

BackgroundThere is a paucity of data on the burden of the full spectrum of community-acquired pneumonia (CAP) and acute otitis media (AOM) from outpatient and inpatient settings across the age spectrum.MethodsWe conducted a population-based retrospective study in Ontario and British Columbia (BC), Canada, to estimate the incidence rate of CAP and AOM in children and adults over a 14-year period using health administrative databases. CAP and AOM cases were identified from outpatient physician consultation and hospitalisation data in both provinces, and from emergency department visit data in Ontario.ResultsDuring 2005–2018, Ontario had 3 607 124 CAP, 172 290 bacterial CAP, 7814 pneumococcal pneumonia, and 8 026 971 AOM cases. The incidence rate of CAP declined from 3077/100 000 in 2005 to 2604/100 000 in 2010 before increasing to 2843/100 000 in 2018; bacterial CAP incidence rate also declined from 178/100 000 in 2005 to 112/100 000 in 2010 before increasing to 149/100 000 in 2018. The incidence rate of AOM decreased from 4192/100 000 in 2005 to 3178/100 000 in 2018. BC had 970 455 CAP, 317 913 bacterial CAP, 35 287 pneumococcal pneumonia and 2 022 871 AOM cases. The incidence rate of CAP in BC decreased from 2214/100 000 in 2005 to 1964/100 000 in 2010 before increasing to 2176/100 000 in 2018; bacterial CAP incidence rate increased from 442/100 000 in 2005 to 981/100 000 in 2018. The incidence rate of AOM decreased from 3684/100 000 in 2005 to 2398/100 000 in 2018. The incidence rate of bacterial CAP increased with age in older adults (≥65 years) with the highest burden in the oldest cohort aged ≥85 years both before and after 13-valent pneumococcal conjugate vaccine (PCV13) programme in both provinces. Hospitalised pneumococcal pneumonia decreased slightly but non-hospitalised pneumococcal pneumonia increased in BC during PCV13 period. No consistent direct benefit of PCV13 on CAP was observed in the paediatric population.ConclusionsThere is a substantial burden of CAP and AOM in Ontario and BC. Indirect benefits from childhood PCV vaccination and polysaccharide vaccination of older adults have not substantially decreased the burden of pneumococcal pneumonia in older adults.

ImportanceDue to high community transmission of the Omicron variant, healthcare workers (HCWs) have been increasingly reporting household exposures to confirmed COVID-19 cases. Quebec (Canada) provincial guidelines required to quarantine these HCWs. Facing the risk of staffing shortages, our hospital decided to allow them to work.ObjectiveTo evaluate the risk for HCWs, who were household contacts, to become positive for COVID-19 by RT-PCR and evaluate the risk of nosocomial COVID-19 transmission.DesignCohort of HCWs with a history of household exposure to a confirmed case of COVID-19.SettingCHU Sainte-Justine, a tertiary care mother and child center in Montreal (QC) CanadaParticipantsConsecutive HCWs who contacted OHS between December 20, 2021 and January 17, 2022 for a history of household exposure to COVID-19.ExposureConfirmed case of COVID-19 in the householdMain outcome and measuresThe main outcome was a positive RT-PCR for SARS-CoV-2. Outbreaks and nosocomial cases were identified through daily analysis of COVID-19 cases, by sector and part of the usual Infection Prevention and Control surveillance process.ResultsOverall, 237 of 475 (50%) HCWs who declared a known household contact with a confirmed COVID-19 case remained negative. Of those who became positive, 196 (82.4%) were positive upon initial testing and were quarantined. Only 42 (15%) of 279 HCWs who were allowed to work became positive, a median of 4 days after the initial test. The absence of symptoms at initial evaluation (OR 3.8, 95% CI 2.5-5.7) and having received a third vaccine dose more than 7 days before (OR 1.88, 95% CI 1.3 – 2.8) were associated with an increased odds of remaining negative. There was no outbreak among HCWs and no nosocomial transmission to patients from a HCW that was allowed to work, while a known household contact.Conclusion and relevanceMeasures taken to protect the health care environment from COVID-19 must be cautiously balanced with the risk of staffing shortage. Allowing vaccinated asymptomatic HCWs who are known household contacts of confirmed COVID-19 cases to work is likely a safe alternative, when staff shortage is anticipated.

Introduction: We aimed to measure the impact of the COVID-19 pandemic on maternal mental health, stratifying on pregnancy status, trimester of gestation, and pandemic period/wave.Methods: Pregnant persons and persons who delivered in Canada during the pandemic, >18 years, were recruited, and data were collected using a web-based strategy. The current analysis includes data on persons enrolled between 06/2020-08/2021. Maternal sociodemographic indicators, mental health measures (Edinburgh Perinatal Depression Scale (EPDS), Generalized Anxiety Disorders (GAD-7), stress) were self-reported. Maternal mental health in pregnant women (stratified by trimester, and pandemic period/wave at recruitment) was compared with mental health of women who had delivered; determinants of severe depression were identified with multivariate logistic regression models.Results: 2,574 persons were pregnant and 626 had already delivered at recruitment. Participants who had delivered had significantly higher mean depressive symptom scores compared to those pregnant at recruitment (9.1 (SD, 5.7) vs. 8.4 (SD, 5.3), p=0.009). Among those who were pregnant at recruitment, depressive symptoms were significantly higher in women recruited in their third trimester, and those recruited during the 2nd wave of the pandemic. Maternal anxiety (aOR 1.51; 95%CI 1.44-1.59) and stress (aOR 1.35; 95%CI 1.24-1.48) were the most significant predictors of severe maternal depression (EDPS˃13) in pregnancy. Conclusion: The COVID-19 pandemic had a significant impact on maternal depression during pregnancy and in the post-partum period. Given that gestational depression/anxiety/stress have been associated with preterm birth and childhood cognitive problems, it is essential to continue following women/children, and develop strategies to reduce COVID-19’s longer-term impact.

To describe the reasoning processes used by pediatric intensivists to make antibiotic-related decisions.Grounded theory qualitative study.Three Canadian university-affiliated tertiary medical, surgical, and cardiac PICUs.Twenty-one PICU physicians.None.We conducted field observation during morning rounds followed by semistructured interviews with participants to examine the clinical reasoning behind antibiotic-related decisions (starting/stopping antibiotics, or treatment duration) made for patients with a suspected/proven bacterial infection. We used a grounded theory approach for data collection and analysis. Thematic saturation was reached after 21 interviews. Of the 21 participants, 10 (48%) were female, 15 (71%) were PICU attending staff, and 10 (48%) had greater than 10 years in clinical practice. Initial clinical reasoning involves using an analytical approach to determine the likelihood of bacterial infection. In case of uncertainty, an assessment of patient safety is performed, which partly overlaps with the use of intuitive clinical reasoning. Finally, if uncertainty remains, physicians tend to consult infectious diseases experts. Factors that override this clinical reasoning process include disease severity, pressure from consultants, and the tendency to continue antibiotic treatment initiated by colleagues.Antibiotic-related decisions for critically ill children are complex, and pediatric intensivists use several clinical reasoning strategies to decrease the uncertainty around the bacterial etiology of infections. However, disease severity and patient safety concerns may overrule decisions based on clinical evidence and lead to antibiotic use. Several cognitive biases were identified in the clinical reasoning processes.

Accurate serologic tests to detect host antibodies to SARS-CoV-2 will be critical for the public health response to the COVID-19 pandemic. This article discusses key use cases for SARS-CoV-2 antibo...

A vaccine for respiratory syncytial virus (RSV) has been actively sought for over 60 years due to the health impacts of RSV disease in infants, but currently the only available preventive measure in Canada and elsewhere is limited to passive immunization for high-risk infants and children with a monoclonal antibody. RSV vaccine development has faced many challenges, including vaccine-induced enhancement of RSV disease in infants. Several key developments in the last decade in the fields of cellular immunology and protein structure have led to new products entering late-stage clinical development. As of July 2019, RSV vaccine development is being pursued by 16 organizations in 121 clinical trials. Five technologies dominate the field of RSV vaccine development, four active immunizing agents (live-attenuated, particle-based, subunit-based and vector-based vaccines) and one new passive immunizing agent (monoclonal antibody). Phase 3 clinical trials of vaccine candidates for pregnant women, infants, children and older adults are under way. The next decade will see a dramatic transformation of the RSV prevention landscape.

Emergency vaccination programs often are needed to control outbreaks of meningococcal disease caused by Neisseria meningitidis serogroup B (MenB) on college campuses. Such campaigns expend multiple campus and public health resources. We conducted a randomized, controlled, multicenter, observer-blinded trial comparing immunogenicity and tolerability of an accelerated vaccine schedule of 0 and 21 days to a longer interval of 0 and 60 days for 4-component MenB vaccine (MenB-4C) in students 17-25 years of age. At day 21 after the first MenB-4C dose, we observed protective human serum bactericidal titers >4 to MenB strains 5/99, H44/76, and NZ 98/254 in 98%-100% of participants. Geometric mean titers increased >22-fold over baseline. At day 180, >95% of participants sustained protective titers regardless of their vaccine schedule. The most common adverse event was injection site pain. An accelerated MenB-4C immunization schedule could be considered for rapid control of campus outbreaks.

Impact of an adolescent tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine program was assessed in the provinces of British Columbia and Quebec, Canada. In both provinces, the Tdap booster has been in place since 2004, targeting Grade 9 students (14-15-years-of-age). Incidence rate ratios (IRRs) standardizing notification rates among teens 15-19-years-old to infants

Introduction Seasonal influenza is an important cause of morbidity and mortality, despite being vaccine-preventable. Sex factors (genes and hormones) seem to impact individuals’ susceptibility to infectious diseases and their response to vaccination. However, most vaccine studies do not explicitly assess sex differences in vaccine response, but rather adjust for sex. Methods We conducted a systematic review to analyze immunogenicity, efficacy, effectiveness and/or safety of seasonal influenza vaccine data stratified by sex. We searched PubMed, EMBASE, CINAHL, Web of Science and clinicaltrials.gov for observational studies and phase III/IV trials from January 1990 to June 2018, published in English or French. Two reviewers independently screened all references, then proceeded to data extraction and quality assessment using the Cochrane tools (RoB and ROBINS-I) on included studies. Results Of the 5,745 citations retrieved, 46 studies were included in the SR. Overall, 18 studies assessed immunogenicity, 1 estimated efficacy, 6 measured effectiveness and 25 evaluated safety of seasonal influenza vaccine in females and males (four studies reported on two sex-stratified outcomes concomitantly). Conclusion No clear conclusion could be drawn regarding the effect of sex on the immunogenicity and effectiveness of seasonal influenza vaccine, but higher rates of adverse events following immunization (AEFIs) were reported in females. The heterogeneity of data and studies’ low quality prevented us from conducting a meta-analysis. There is a need to emphasize on the appropriate use of the terms sex and gender in biomedical research. Evidence of higher quality is needed to better understand sex differences in response to influenza vaccine.

Studies of acute gastroenteritis (AGE) are hampered by the lack of routine diagnostic methods with good sensitivity and specificity. Molecular methods are increasingly used for clinical purposes, but the clinical significance of a positive result remains a challenge. In this study we aimed to compare results of routine diagnostic methods and molecular methods in symptomatic children and asymptomatic controls.Patients presenting to the pediatric emergency departments of two university hospitals in Brussels with AGE were recruited prospectively from May 2015 to October 2016; asymptomatic controls were recruited from the same hospitals. Stool analyses were performed for all participants for common pathogenic bacteria (culture), virus (immunochromatography) and parasites (microscopy). Stools were also analysed with the Luminex Gastrointestinal Pathogen Panel, a multiplex-PCR for common enteropathogens.Stools from 178 patients and 165 controls were analysed. An enteropathogen was detected in 62.4% (111/178) of cases when combining the two methods (56.2% (100/178) by Luminex, 42.7% (76/178) with routine methods) and 29.1% (48/165) of controls (24.2% (40/165) by Luminex and 10.3% (17/165) by routine methods). Some pathogens were detected more often with Luminex than with routine methods, such as Salmonella (16.3% (29/178) with Luminex and 3.9% (7/178) with routine method, p 0.05), whereas others identified by culture methods, such as Campylobacter, Shigella, Yersinia, were missed by Luminex.Molecular tools seem attractive methods, providing high positivity and a rapid turn-around time for the diagnosis of AGE. However, high rates of positivity in both cases and controls highlight the difficulty in interpreting results. Pathogens missed by Luminex but detected by culture methods raise more questions about the true clinical interest of the technique for our patients.

Urinary tract infections caused by the bacterium Escherichia coli are among the most frequently encountered infections and are a common reason for antimicrobial prescriptions. Resistance to fluoroquinolone antimicrobial agents, particularly ciprofloxacin, has increased in recent decades. It is intuitive that variation in fluoroquinolone resistance is driven by changes in antimicrobial use, but careful study of this association requires the use of time-series methods. Between April 2010 and December 2014, we studied seasonal variation in resistance to ciprofloxacin, trimethoprim-sulfamethoxazole, and ampicillin in community-acquired urinary E. coli isolates in Montreal, Quebec, Canada. Using dynamic linear models, we investigated whether seasonal variation in resistance could be explained by seasonal variation in community antimicrobial use. We found a positive association between total fluoroquinolone use lagged by 1 and 2 months and the proportion of isolates resistant to ciprofloxacin. Our results suggest that resistance to ciprofloxacin is responsive to short-term variation in antimicrobial use. Thus, antimicrobial stewardship campaigns to reduce fluoroquinolone use, particularly in the winter when use is highest, are likely to be a valuable tool in the struggle against antimicrobial resistance.

BACKGROUND The use of bacterial multiplex polymerase chain reaction (PCR) in children with suspected pertussis sometimes yields unexpected positive results for Mycoplasma pneumoniae. We aimed to evaluate the clinical significance of positive M. pneumoniae results in this population. METHODS Retrospective cohort of consecutive patients with suspected pertussis tested with a bacterial multiplex PCR (including Bordetella pertussis and M. pneumoniae) between June 2015 and March 2017. Medical records were reviewed to compare demographics, clinical presentations and outcomes of patients positive for M. pneumoniae with those positive for B. pertussis and those with negative results, using multivariable logistic regression. RESULTS A total of 1244 patients were included as follows: 56 (4.5%) with M. pneumoniae, 116 (9.3%) with B. pertussis and 1029 (82.7%) with negative results. Mean age was respectively 4.8 years, 6.5 years and 2.8 years (P < 0.05). Children with M. pneumoniae were less likely to present with cardinal symptoms of pertussis such as paroxysmal cough [adjusted odds ratio (OR): 0.19, 95% confidence interval (CI): 0.08-0.40) but were more likely to have fever (adjusted OR: 10.53, 95% CI: 3.54-39.49) and other nonspecific respiratory symptoms compared with children with B. pertussis. Children with M. pneumoniae had very similar clinical presentations to those with a negative PCR, but were more likely to have radiologically confirmed pneumonia (adjusted OR: 5.48, 95% CI: 2.96-9.99) and were less likely to be diagnosed with a concomitant viral infection (adjusted OR: 0.32, 95% CI: 0.07-0.99). CONCLUSIONS In children with suspected pertussis, the detection of M. pneumoniae is clinically relevant. However, the impact of this finding on patients' outcome is still unclear.

Molecular typing methods are used to characterize the relatedness between bacterial isolates involved in infections. These approaches rely mostly on discrete loci or whole-genome sequencing (WGS) analyses of pure cultures. On the other hand, their application to environmental DNA profiling to evaluate epidemiological relatedness among patients and environments has received less attention. We developed a specific, high-throughput short sequence typing (HiSST) method for the opportunistic human pathogen Serratia marcescens. Genes displaying the highest polymorphism were retrieved from the core genome of 60 S. marcescens strains. Bioinformatics analyses showed that use of only three loci (within bssA, gabR, and dhaM) distinguished strains with a high level of efficiency. This HiSST scheme was applied to an epidemiological survey of S. marcescens in a neonatal intensive care unit (NICU). In a first case study, a strain responsible for an outbreak in the NICU was found in a sink drain of this unit, by using HiSST scheme and confirmed by WGS. The HiSST scheme was also applied to environmental DNA extracted from sink-environment samples. Diversity of S. marcescens was modest, with 11, 6, and 4 different sequence types (ST) of gabR, bssA, and dhaM loci among 19 sink drains, respectively. Epidemiological relationships among sinks were inferred on the basis of pairwise comparisons of ST profiles. Further research aimed at relating ST distribution patterns to environmental features encompassing sink location, utilization, and microbial diversity is needed to improve the surveillance and management of opportunistic pathogens. IMPORTANCE Serratia marcescens is an important opportunistic human pathogen, often multidrug resistant and involved in outbreaks of nosocomial infections in neonatal intensive care units. Here, we propose a quick and user-friendly method to select the best typing scheme for nosocomial outbreaks in relating environmental and clinical sources. This method, named high-throughput short sequence typing (HiSST), allows to distinguish strains and to explore the diversity profile of nonculturable S. marcescens. The application of HiSST profile analysis for environmental DNA offers new possibilities to track opportunistic pathogens, identify their origin, and relate their distribution pattern with environmental features encompassing sink location, utilization, and microbial diversity. Adaptation of the method to other opportunistic pathogens is expected to improve knowledge regarding their ecology, which is of significant interest for epidemiological risk assessment and elaborate outbreak mitigation strategies.

Key Points Question What is the seroprevalence of SARS-CoV-2 antibodies in a convenience sample of children aged 2 to 17 years in Montreal, Canada, enrolled between October 2020 and March 2021? Findings In this cohort study of 1632 participants, the mean baseline seroprevalence of SARS-CoV-2 was 5.8%. Of the 95 participants who were seropositive for SARS-CoV-2 antibodies, 82% were not tested or tested negative, and all experienced either mild or no clinical symptoms. Meaning The findings suggest that there was more transmission occurring in children compared with what was being detected, although children experienced few or mild symptoms., This cohort study estimates the seroprevalence of SARS-CoV-2 antibodies in children and teenagers in 4 neighborhoods of Montreal, Canada., Importance Quebec prioritized in-person learning after the first wave of the COVID-19 pandemic, with school closures being implemented temporarily in selected schools or in hot-spot areas. Quebec’s decision to keep most schools open was controversial, especially in Montreal, which was the epicenter of Canada’s first and second waves; therefore, understanding the extent to which children were infected with SARS-CoV-2 provides important information for decisions about school closures. Objective To estimate the seroprevalence of SARS-CoV-2 antibodies in children and teenagers in 4 neighborhoods of Montreal, Canada. Design, Setting, and Participants This cohort study (the Enfants et COVID-19: Étude de séroprévalence [EnCORE] study) enrolled a convenience sample of children aged 2 to 17 years between October 22, 2020, and March 22, 2021, in Montreal, Canada. Exposures Potential exposure to SARS-CoV-2. Main Outcomes and Measures The main outcome was seroprevalence of SARS-CoV-2 antibodies, collected using dried blood spots (DBSs) and analyzed with a research-based enzyme-linked immunosorbent assay (ELISA). Parents also completed an online questionnaire that included questions on self-reported COVID-19 symptoms and tests, along with sociodemographic questions. Results This study included 1632 participants who provided a DBS sample from 30 day cares, 22 primary schools, and 11 secondary schools. The mean (SD) age of the children who provided a DBS sample was 9.0 (4.4) years; 801 (49%) were female individuals, with 354 participants (22%) from day cares, 725 (44%) from primary schools, and 553 (34%) from secondary schools. Most parents had at least a bachelor’s degree (1228 [75%]), and 210 (13%) self-identified as being a racial or ethnic minority. The mean seroprevalence was 5.8% (95% CI, 4.6%-7.0%) but increased over time from 3.2% (95% CI, 0.7%-5.8%) in October to November 2020 to 8.4% (95% CI, 4.4%-12.4%) in March to April 2021. Of the 95 children with positive SARS-CoV-2 antibody results, 78 (82%) were not tested or tested negative with reverse transcription–polymerase chain reaction (RT-PCR) testing, and all experienced mild (49 [52%]) or no clinical symptoms (46 [48%]). The children of parents who self-identified as belonging to a racial and ethnic minority group were more likely to be seropositive compared with children of White parents (adjusted seroprevalence ratio, 1.9; 95% CI, 1.1-2.6). Conclusions and Relevance These results provide a benchmark of the seroprevalence status in Canadian children. The findings suggest that there was more transmission occurring in children compared with what was being detected by RT-PCR, although children experienced few or mild symptoms. It will be important to continue monitoring the serological status of children, particularly in the context of new COVID-19 variants of concern and in the absence of mass vaccination campaigns targeting young children.

BackgroundWe evaluated the use of rapid antigen detection tests (RADT) for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in school settings to determine RADT’s performance compared to PCR.MethodsIn this real-world, prospective observational cohort study, high-school students and staff were recruited from two high-schools in Montreal (Canada) and followed from January 25th to June 10th, 2021. Twenty-five percent of asymptomatic participants were tested weekly by RADT (nasal) and PCR (gargle). Class contacts of cases were tested. Symptomatic participants were tested by RADT (nasal) and PCR (nasal and gargle). The number of cases and outbreaks were compared to other high schools in the same area.ResultsOverall, 2,099 students and 286 school staff members consented to participate. The overall RADT’s specificity varied from 99.8 to 100%, with a lower sensitivity, varying from 28.6% in asymptomatic to 83.3% in symptomatic participants. Secondary cases were identified in 10 of 35 classes. Returning students to school after a 7-day quarantine, with a negative PCR on D6-7 after exposure, did not lead to subsequent outbreaks. Of cases for whom the source was known, 37 of 57 (72.5%) were secondary to household transmission, 13 (25%) to intra-school transmission and one to community contacts between students in the same school.ConclusionRADT did not perform well as a screening tool in asymptomatic individuals. Reinforcing policies for symptom screening when entering schools and testing symptomatic individuals with RADT on the spot may avoid subsequent significant exposures in class.Table of Contents SummaryRapid antigen tests were compared to standard PCR to diagnose SARS-CoV-2 infections in high-school students. They performed better in symptomatic individuals.What’s Known on This SubjectRapid antigen detection tests (RADT) are often used to diagnose respiratory pathogens at the point-of-care. Their performance characteristics vary, but they usually have high specificity and moderate sensitivity compared with PCR.What This Study AddsRADT sensitivity ranged from 28.6% in asymptomatic individuals to 83.3% in symptomatic individuals. Return to school after 7 days of quarantine was safe in exposed students. Secondary cases were identified in 28% of classes with an index case.

OBJECTIVES To determine the association between the implementation of an antimicrobial stewardship program at a local PICU and to determine the association between the presence of an antimicrobial stewardship programs and antimicrobial use across three Canadian PICUs, among critically ill children with bronchiolitis. DESIGN A multicenter retrospective cohort study. SETTING Three Canadian PICUs over two winter seasons. INTERVENTIONS An antimicrobial stewardship program was implemented at PICU 1 at the end of season 1. PATIENTS Patients less than or equal to 2 years old admitted with bronchiolitis. MEASUREMENTS AND MAIN RESULTS We used regression models with an interaction term between site (PICU 1 and PICU 2) and season (1 and 2) as the primary analysis to determine the association between implementation of an antimicrobial stewardship program at PICU 1 and 1) the proportion of antimicrobials discontinued 72 hours after hospital admission (logistic regression), 2) antimicrobial treatment duration (negative binomial regression), and 3) antimicrobial prescriptions within 48 hours of hospital admission (logistic regression). As a secondary analysis, we determined the association between having an antimicrobial stewardship program present and the aforementioned outcomes across the three PICUs. A total of 372 patients were included. During seasons 1 and 2, median age was 2.2 months (interquartile range, 1.2-6.2 mo) and 2.1 months (interquartile range, 1.3-6.8 mo), respectively. Among patients with viral bronchiolitis, implementation of an antimicrobial stewardship program at PICU 1 was associated with increased odds of discontinuing antimicrobials (odds ratio, 25.63; 95% CI, 2.86-326.29), but not with antimicrobial duration (odds ratio, 0.56; 95% CI, 0.31-1.02) or antimicrobial prescriptions (odds ratio, 0.33; 95% CI, 0.10-1.04). The presence of an antimicrobial stewardship program was similarly associated with antimicrobial discontinuation among patients with viral bronchiolitis (odds ratio, 20.79; 95% CI, 2.46-244.92), but not with antimicrobial duration (odds ratio, 0.57; 95% CI, 0.32-1.03) or antimicrobial prescriptions (odds ratio, 0.37; 95% CI, 0.12-1.11). CONCLUSIONS Antimicrobial stewardship programs were associated with increased likelihood of discontinuing antimicrobial treatments in the PICU patients with viral bronchiolitis. However, larger studies are needed to further determine the role of an antimicrobial stewardship programs in reducing unnecessary antimicrobial use in this patient population.

SignificanceThe primary method of COVID-19 detection is reverse transcription polymerase chain reaction (RT-PCR) testing. PCR test sensitivity may decrease as more variants of concern arise.AimWe aimed to develop a reagent-free way to detect COVID-19 in a real-world setting with minimal constraints on sample acquisition.ApproachWe present a workflow for collecting, preparing and imaging dried saliva supernatant droplets using a non-invasive, label-free technique – Raman spectroscopy – to detect changes in the molecular profile of saliva associated with COVID-19 infection.ResultsUsing machine learning and droplet segmentation, amongst all confounding factors, we discriminated between COVID-positive and negative individuals yielding receiver operating coefficient (ROC) curves with an area under curve (AUC) of 0.8 in both males (79% sensitivity, 75% specificity) and females (84% sensitivity, 64% specificity). Taking the sex of the saliva donor into account increased the AUC by 5%.ConclusionThese findings may pave the way for new rapid Raman spectroscopic screening tools for COVID-19 and other infectious diseases.

The primary method of COVID-19 detection is reverse transcription polymerase chain reaction (RT-PCR) testing. PCR test sensitivity may decrease as more variants of concern arise and reagents may become less specific to the virus.We aimed to develop a reagent-free way to detect COVID-19 in a real-world setting with minimal constraints on sample acquisition. The machine learning (ML) models involved could be frequently updated to include spectral information about variants without needing to develop new reagents.We present a workflow for collecting, preparing, and imaging dried saliva supernatant droplets using a non-invasive, label-free technique-Raman spectroscopy-to detect changes in the molecular profile of saliva associated with COVID-19 infection.We used an innovative multiple instance learning-based ML approach and droplet segmentation to analyze droplets. Amongst all confounding factors, we discriminated between COVID-positive and COVID-negative individuals yielding receiver operating coefficient curves with an area under curve (AUC) of 0.8 in both males (79% sensitivity and 75% specificity) and females (84% sensitivity and 64% specificity). Taking the sex of the saliva donor into account increased the AUC by 5%.These findings may pave the way for new rapid Raman spectroscopic screening tools for COVID-19 and other infectious diseases.

Background Invasive pneumococcal disease (IPD) burden, evaluated in Canada using reported confirmed cases in surveillance systems, is likely underestimated due to underreporting. We estimated the burden of IPD in Ontario and British Columbia (BC) by combining surveillance data with health administrative databases. Methods We established a cohort of 27,525 individuals in Ontario and BC. Laboratory-confirmed IPD cases were identified from Ontario’s integrated Public Health Information System and the BC Centre for Disease Control Public Health Laboratory. Possible IPD cases were identified from hospitalization data in both provinces, and from emergency department visit data in Ontario. We estimated the age and sex adjusted annual incidence of IPD and pneumococcal conjugate/polysaccharide vaccine (PCV/PPV) serotype-specific IPD using Poisson regression models. Results In Ontario, 20,205 overall IPD cases, including 15,299 laboratory-confirmed cases, were identified with relatively stable age- and sex-adjusted annual incidence rates ranging from 13.7/100,000 (2005) to 13.6/100,000 (2018). In BC, 7,320 overall IPD cases, including 5,932 laboratory-confirmed cases were identified; annual incidence rates increased from 10.9/100,000 (2002) to 13.2/100,000 (2018). Older adults aged ≥ 85 years had the highest incidence rates. During 2007–2018 the incidence of PCV7 serotypes and additional PCV13 serotypes decreased while the incidence of unique PPV23 and non-vaccine serotypes increased in both provinces. Conclusions IPD continues to cause a substantial public health burden in Canada despite publicly funded pneumococcal vaccination programs, resulting in part from an increase in unique PPV23 and non-vaccine serotypes.

Objectives Rapid identification and isolation of SARS-CoV-2 cases are priorities in school and child care settings to prevent further outbreaks. The objective of this study was to compare the clinical presentation of SARS-CoV-2 infections among preschool ( Methods Retrospective study of children (≤18 years of age) diagnosed with SARS-CoV-2 in the outpatient COVID-19 clinic or the Emergency Department at the Centre Hospitalier Universitaire Sainte-Justine (Montreal, Quebec, Canada) February through May 2020. Results Of 3,789 children tested, 105 (3%) were positive for SARS-CoV-2, and 104 included in the analysis (n=49 age Conclusions While there are differences in the clinical manifestations of COVID-19 in preschool- versus school-aged children, in both age groups, isolated rhinorrhea was not a manifestation of SARS-CoV-2 infection. These results could help further guide testing criteria and exclusion criteria in child care and school settings.

Molecular typing methods are used to characterize the relatedness between bacterial isolates involved in infections. These approaches rely mostly on discrete loci or whole genome sequences (WGS) analyses of pure cultures. On the other hand, their application to environmental DNA profiling to evaluate epidemiological relatedness amongst patients and environments has received less attention. We developed a specific, high-throughput short sequence typing (HiSST) method for the opportunistic human pathogen Serratia marcescens. Genes displaying the highest polymorphism were retrieved from the core genome of 60 S. marcescens strains. Bioinformatics analyses showed that use of only three loci (within bssA, gabR and dhaM) distinguished strains with the same level of efficiency than average nucleotide identity scores of whole genomes. This HiSST scheme was applied to an epidemiological survey of S. marcescens in a neonatal intensive care unit (NICU). In a first case study, a strain responsible for an outbreak in the NICU was found in a sink drain of this unit, by using HiSST scheme and confirmed by WGS. The HiSST scheme was also applied to environmental DNA extracted from sink-environment samples. Diversity of S. marcescens was modest, with 11, 6 and 4 different sequence types (ST) of gabR, bssA and dhaM loci amongst 19 sink drains, respectively. Epidemiological relationships amongst sinks were inferred on the basis of pairwise comparisons of ST profiles. Further research aimed at relating ST distribution patterns to environmental features encompassing sink location, utilization and microbial diversity is needed to improve the surveillance and management of opportunistic pathogens.

IntroductionFurther evidence is needed to understand the contribution of schools and daycares for the spread of COVID-19 in the context of diverse transmission dynamics and continually evolving public health interventions. The Enfants et COVID-19: Étude de séroprévalence (EnCORE) study will estimate the seroprevalence and seroconversion of SARS-CoV-2 among school and daycare children and personnel. In addition, the study will examine associations between seroprevalence and sociodemographic characteristics and reported COVID-19 symptoms and tests, and investigates changes in health, lifestyle and well-being outcomes.Methods and analysisThis study includes children and personnel from 62 schools and daycares in four neighbourhoods in Montreal, Canada. All children aged 2–17 years attending one of the participating schools or daycares and their parents are invited to participate, as well as a sample of personnel members. Participants respond to brief questionnaires and provide blood samples, collected via dried blood spot, at baseline (October 2020–March 2021) and follow-up (May–June 2021). Questionnaires include sociodemographic and household characteristics, reported COVID-19 symptoms and tests, potential COVID-19 risk factors and prevention efforts and health and lifestyle information. Logistic regression using generalised estimating equations will be used to estimate seroprevalence and seroconversion, accounting for school-level clustering.Ethics and disseminationThis study was approved by the research ethics boards of the Université de Montréal (CERSES) and the Centre Hospitalier Universitaire Sainte-Justine. Results will contribute to our knowledge about SARS-CoV-2 transmission in schools and daycares and will be made available to study participants and their families, school and public health decision-makers and the research community.

BackgroundThe success of current and prospective COVID-19 vaccine campaigns for children and adolescents will in part depend on the willingness of parents to accept vaccination. This study examined social determinants of parental COVID-19 vaccine acceptance and uptake for children and adolescents.MethodsWe used cross-sectional data from an ongoing COVID-19 cohort study in Montreal, Canada and included all parents of 2 to 18-year-olds who completed an online questionnaire between May 18 and June 26, 2021 (n=809). We calculated child age-adjusted prevalence estimates of vaccine acceptance by parental education, race/ethnicity, birthplace, household income, and neighbourhood, and used multinomial logistic regression to estimate adjusted prevalence differences (aPD) and ratios (aPR). Social determinants of vaccine uptake were estimated for the vaccine-eligible sample of 12 to 18 year-olds (n=306).ResultsIntention to vaccinate children against COVID-19 was high, with only 12.4% of parents unlikely to have their child vaccinated. Parents with younger children were less likely to accept vaccination, as were those from lower-income households, racialized groups, and those born outside Canada. The percent of parents whose child was vaccinated or very likely to be vaccinated was 18.4 percentage points lower among those with annual household incomes InterpretationThis study identified marked social inequalities in COVID-19 vaccine acceptance and uptake for children and adolescents. Efforts are needed to reach disadvantaged and marginalized populations with tailored strategies that promote informed decision making and facilitate access to vaccination.

Background:Banked human milk (BHM) has inherent infectious risks, even when pasteurized. Because of the ubiquity ofBacillus cereusin the environment and its ability to resist the Holder pasteurization process, there is a concern that BHM might lead to severeB. cereusinfections.Objective:We reviewed observed and published cases to determine the potential causal role of BHM as the source of these infections.Methods:Two infants in the province of Québec (Canada) developed aB. cereusneonatal infection, and both had received BHM. We conducted bacteriological studies to compare clinical isolates and those found in these cases.Results:After extended culture of BHM retention lots,B. cereuswas found to have been involved in batches related to the first case. However, molecular typing showed that the strain was different from the clinical isolate, therefore excluding BHM as the source of contamination. In the second case, aBrevibacillusspp was isolated, a species distinct from the clinical isolate.Conclusion:Based on these cases and others reported in the literature, a causal link betweenB. cereuscontaminated BHM and preterm neonatal infection has never been documented. Therefore, the risk that BHM can cause this infection remains theoretical. Given the widespread presence ofB. cereusin the hospital environment and its capacity to resist standard cleaning procedures, it seems likely that airborne or direct or indirect contact are the main sources of most, if not all, cases of severeB. cereusneonatal infections, even in babies exposed to BHM.

Introduction Although a vaccine-preventable disease, influenza causes approximately 3–5 million cases of severe illness and about 290,000–650,000 deaths worldwide, which occur primarily among people 65 years and older. Nonetheless, prevention of influenza and its complications rely mainly on vaccination. We aimed to systematically evaluate influenza vaccine effectiveness at reducing healthcare utilization in older adults, defined as the reduction of outpatient visits, ILI and influenza hospitalizations, utilization of antibiotics and cardiovascular events by vaccination status during the influenza season. Methods We searched MEDLINE, EMBASE, CINAHL, Cochrane Library and considered any seasonal influenza vaccine, excluding the pandemic (2009–10 season) vaccine. Reviewers independently assessed data extraction and quality assessment. Results Of the 8308 citations retrieved, 22 studies were included in the systematic review. Overall, two studies (9%) were deemed at moderate risk of bias, thirteen (59%) at serious risk of bias and seven (32%) at critical risk of bias. For outpatient visits, we found modest evidence of protection by the influenza vaccine. For all-cause hospitalization outcomes, we found a wide range of results, mostly deemed at serious risk of bias. The included studies suggested that the vaccine may protect older adults against influenza hospitalizations and cardiovascular events. No article meeting our inclusion criteria explored the use of antibiotics and ILI hospitalizations. The high heterogeneity between studies hindered the aggregation of data into a meta-analysis. Conclusion The variability between studies prevented us from drawing a clear conclusion on the effectiveness of the influenza vaccine on healthcare utilization in older adults. Overall, the data suggests that the vaccine may result in a reduction of healthcare utilization in the older population. Further studies of higher quality are necessary.

Historically, Bartonella spp. have been associated with febrile illness (Oroya fever, trench fever, and cat scratch disease), endocarditis (numerous Bartonella spp.), and vasoproliferative lesions (Bartonella bacilliformis, Bartonella quintana, Bartonella henselae, and Bartonella vinsonii subsp. berkhoffii), occurring most often but not exclusively in immunocompromised patients. Recently, bloodstream infections with various Bartonella spp. have been documented in nonimmunocompromised individuals in association with a spectrum of cardiovascular, neurologic, and rheumatologic symptoms. As documented in this family, symptoms for which the medical implications remain unclear can occur in multiple family members infected with one or more Bartonella spp. Serial serologic and molecular microbiological findings supported exposure to or infection with Bartonella spp. in all seven family members. Either antibiotics failed to eliminate bacteremic infection, resulted in partial resolution of symptoms, or potentially reinfection occurred during the 19-month study period. There is a substantial need for clinical research to clarify the extent to which Bartonella spp. bacteremia induces nonspecific cardiovascular, neurologic, or rheumatologic symptoms, for ongoing improvement in the sensitivity and specificity of diagnostic testing, and clarification as to if, when, and how to treat patients with documented Bartonella spp. bacteremia.

Objective:BACTOT, Quebec’s healthcare-associated bloodstream infection (HABSI) surveillance program has been operating since 2007. In this study, we evaluated the changes in HABSI rates across 10 years of BACTOT surveillance under a Bayesian framework.Design:A retrospective, cohort study of eligible hospitals having participated in BACTOT for at least 3 years, regardless of their entry date. Multilevel Poisson regressions were fitted independently for cases of HABSI, catheter-associated bloodstream infections (CA-BSIs), non–catheter-associated primary BSIs (NCA-BSIs), and BSIs secondary to urinary tract infections (BSI-UTIs) as the outcome and log of patient days as the offset. The log of the mean Poisson rate was decomposed as the sum of a surveillance year effect, period effect, and hospital effect. The main estimate of interest was the cohort-level rate in years 2–10 of surveillance relative to year 1.Results:Overall, 17,479 cases and 33,029,870 patient days were recorded for the cohort of 77 hospitals. The pooled 10-year HABSI rate was 5.20 per 10,000 patient days (95% CI, 5.12–5.28). For HABSI, CA-BSI, and BSI-UTI, there was no difference between the estimated posterior rates of years 2–10 compared to year 1. The posterior means of the NCA-BSI rate ratios increased from the seventh year until the tenth year, when the rate was 29% (95% confidence interval, 1%–89%) higher than the first year rate.Conclusions:HABSI rates and those of the most frequent subtypes remained stable over the surveillance period. To achieve reductions in incidence, we recommend that more effort be expended in active interventions against HABSI alongside surveillance.