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BACKGROUND Premature development of cardiovascular disease in children living with HIV-1 (CLWH) may be associated with compromised gut barrier function, microbial translocation, immune activation, systemic inflammation and endothelial activation. Biomarkers of these pathways may provide insights into pathogenesis of atherosclerotic disease in CLWH. METHODS This was a cross-sectional study of CLWH enrolled in the multicentre Early Pediatric Initiation-Canadian Child Cure Cohort (EPIC4 ) who were on antiretroviral therapy (ART) with undetectable viral load. Plasma biomarkers of intestinal epithelial injury [intestinal fatty acid binding protein-1 (IFABP)], systemic inflammation [tumour necrosis factor (TNF) and interleukin-6 (IL-6)] and endothelial activation [angiopoietin-2 (Ang2), soluble vascular endothelial growth factor-1 (sVEGFR1) and soluble endoglin (sEng)] were quantified by enzyme-linked immunosorbent assay. Correlation and factor analysis of biomarkers were used to examine associations between innate immune pathways. RESULTS Among 90 CLWH, 16% of Ang2, 15% of sVEGFR1 and 23% of sEng levels were elevated relative to healthy historic controls. Pairwise rank correlations between the three markers of endothelial activation were statistically significant (ρ = 0.69, ρ = 0.61 and ρ = 0.65, P

Background Neurological adverse events following immunization (AEFI) remain poorly characterized. Our objective was to describe pediatric acute and chronic encephalopathy and encephalitis cases following immunization reported via active sentinel surveillance from 1992 to 2012. Methods This case series provides a descriptive analysis of encephalopathy/encephalitis admissions reported to the Canadian Immunization Monitoring Program ACTive (IMPACT). Acute cases were reported if symptom onset (seizures, decreased level of consciousness, change in mental status) occurred 0–7 days after tetanus or pertussis-containing vaccines, 0–15 days after other inactivated vaccines, or 5–30 days after live vaccines. Chronic cases of subacute sclerosing panencephalitis or subacute progressive rubella encephalitis were reported at any interval after vaccination. Clinical data were examined to identify possible causes for encephalopathy/encephalitis other than vaccination. Results Sixty-one cases of encephalopathy/encephalitis following immunization were reported to IMPACT over 21 years; 57 (93.4%) were classified as acute and 4 (6.6%) were chronic cases of subacute sclerosing panencephalitis. Most patients (73.8%) were previously healthy and immunocompetent. The vaccines most frequently administered prior to presentation were diphtheria-tetanus-pertussis, measles-mumps-rubella, and influenza. At discharge, 38 patients (62.3%) had normal neurological status or were expected to recover. Forty patients (70.2%) with acute encephalopathy/encephalitis had a more likely alternate etiology besides vaccination based on neuroimaging, symptoms suggestive of infection, laboratory-confirmed non-vaccine-related infection, or clinical diagnosis. No cases of encephalitis were causally associated with pertussis or influenza vaccines. Two patients (50%) with subacute sclerosing panencephalitis had known wild-type measles infection prior to immunization. Three deaths were reported during hospitalization (4.9%); all were acute encephalitis/encephalopathy cases and none were confirmed to be vaccine-related. Conclusions Encephalopathy/encephalitis following immunization remains a rare but serious adverse event. Most cases had another more likely etiology than vaccination. Continued monitoring and analysis of AEFI is paramount to ensure the safety of immunization programs.

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.

Contexte : TrumenbaMC, un vaccin bivalent contre l’infection invasive à méningocoque du sérogroupe B (MenB-fHBP) de la protéine liant le facteur H, a été autorisé au Canada en octobre 2017 pour la prévention de l’infection invasive à méningocoque causée par la bactérie Neisseria meningitidis du sérogroupe B chez les personnes âgées de 10 à 25 ans. Le Comité consultatif national de l’immunisation (CCNI) formule des recommandations à l’Agence de santé publique du Canada sur l’utilisation des vaccins contre le méningocoque. Objectif : Résumer les recommandations du CCNI concernant l’utilisation du vaccin MenB-fHBP au Canada. Méthodes : Le groupe de travail du CCNI sur l’infection à méningocoque a élaboré une stratégie de recherche prédéfinie en vue de dresser la liste de toutes les études admissibles, en évaluer leur qualité, et résumer et analyser leurs résultats. Selon le processus fondé sur des données probantes du CCNI, le groupe de travail a ensuite proposé des recommandations et déterminé la qualité des évidences à l’appui. À la lumière des données probantes, les recommandations ont ensuite été examinées et approuvées par le CCNI. Résultats : Les deux vaccins contre le méningocoque du sérogroupe B présentement autorisés au Canada ne sont pas interchangeables puisqu’ils contiennent des antigènes différents et qu’il n’existe aucune étude publiée sur l’immunogénicité d’une série de vaccins conjuguant les deux produits. À la suite de l’examen des données probantes, le CCNI recommande l’utilisation du vaccin MenB-fHBP chez les personnes de 10 ans et plus dans les situations où un vaccin contre l’infection invasive à méningocoque du sérogroupe B devrait être proposé : 1) au cours d’une éclosion des cas d’infection à méningocoque du sérogroupe B ou lors de l’émergence de souches hyperendémiques de N. meningitidis qui devraient être réceptives au vaccin; 2) pour la protection des sujets en contact étroit avec un cas d’infection invasive à méningocoque attribué à N. meningitidis du sérogroupe B; 3) pour les sujets atteints de problèmes de santé sous-jacents les exposant à un risque de méningococcie supérieur à celui de l’ensemble de la population; ou 4) pour les sujets présentant un risque d’exposition aux isolats de méningococcique du sérogroupe B supérieur à celui de l’ensemble de la population. Le CCNI recommande également de considérer le vaccin MenB-fHBP comme une option pour les personnes âgées de 10 à 25 ans qui ne présentent pas un risque de méningococcie supérieur à celui de l’ensemble de la population, mais qui souhaitent réduire leur risque de contracter une infection invasive à méningocoque du sérogroupe B. Conclusion : Le CCNI recommande toujours d’offrir un vaccin contre l’infection invasive à méningocoque du sérogroupe B à tous les sujets qui sont à plus haut risque d’infection en raison d’un problème de santé sous-jacent ou un majeur risque d’exposition. En plus de fournir des conseils relatifs aux décideurs en santé publique (c.-à-d. les provinces et les territoires qui prennent des décisions concernant les programmes publiques de vaccination), ces recommandations du CCNI fournissent des renseignements aux particuliers, aux fournisseurs de vaccins et aux organisations sur les vaccins qui ne sont peut-être pas actuellement inclus dans les programmes publiques de vaccination. Le CCNI continue de ne pas recommander l’utilisation des vaccins du sérogroupe B dans les programmes universels canadiens de vaccination systématique pour le moment.

To estimate the risk of recurrence of adverse events following immunization (AEFIs) upon revaccination and to determine among patients with suspected vaccine allergy whether allergy skin test positivity was associated with AEFI recurrence.This prospective observational study included patients assessed in the Canadian Special Immunization Clinic Network from 2013 to 2019 with AEFIs who required revaccination with the vaccine temporally associated with their AEFI. Participants underwent standardized assessment and data collection. Special Immunization Clinic physicians used guidelines to inform their recommendations. Participants were followed up after revaccination to capture AEFI recurrences. Data were transferred to a central database for descriptive analysis.Overall, 588 participants were assessed for 627 AEFIs; 570 (91%) AEFIs occurred in children18 years of age. AEFIs included immediate hypersensitivity (130/627; 21%), large local reactions (110/627; 18%), nonurticarial rash (51/627; 8%), seizures (26/627; 4%), and thrombocytopenia (11/627; 2%). Revaccination was recommended to 513 of 588 (87%) participants. Among participants recommended and due for revaccination during the study period, 63% (299/477) were revaccinated. AEFI recurrence was 10% (31/299) overall, 31% (15/49) for large local reactions, and 7% (5/66) for immediate hypersensitivity. No recurrence was serious. Among 92 participants with suspected vaccine allergy who underwent skin testing and were revaccinated, the negative predictive value of skin testing for AEFI recurrence was 96% (95% CI 92.5%-99.5%).Most individuals with AEFIs were safely revaccinated. Among those with suspected vaccine allergy, skin testing may help determine the safety of revaccination.

OBJECTIVES Antivirals are recommended for children hospitalized with influenza but are underutilized. We describe antiviral prescribing during influenza admissions in Canadian pediatric centers and identify factors associated with antiviral use. METHODS We performed active surveillance for laboratory-confirmed influenza hospitalizations among children ≤16 years old at the 12 Canadian Immunization Monitoring Program Active hospitals, from 2010–2011 to 2018–2019. Logistic regression analyses were used to identify factors associated with antiviral use. RESULTS Among 7545 patients, 57.4% were male; median age was 3 years (interquartile range: 1.1–6.3). Overall, 41.3% received antiviral agents; 72.8% received antibiotics. Antiviral use varied across sites (range, 10.2% to 81.1%) and influenza season (range, 19.9% to 59.6%) and was more frequent in children with ≥1 chronic health condition (52.7% vs 36.7%; P < .001). On multivariable analysis, factors associated with antiviral use included older age (adjusted odds ratio [aOR] 1.04 [95% confidence interval (CI), 1.02–1.05]), more recent season (highest aOR 9.18 [95% CI, 6.70–12.57] for 2018–2019), admission during peak influenza period (aOR 1.37 [95% CI, 1.19–1.58]), availability of local treatment guideline (aOR 1.54 [95% CI, 1.17–2.02]), timing of laboratory confirmation (highest aOR 2.67 [95% CI, 1.97–3.61] for result available before admission), presence of chronic health conditions (highest aOR 4.81 [95% CI, 3.61–6.40] for cancer), radiographically confirmed pneumonia (aOR 1.39 [95% CI, 1.20–1.60]), antibiotic treatment (aOR 1.51 [95% CI, 1.30–1.76]), respiratory support (1.57 [95% CI, 1.19–2.08]), and ICU admission (aOR 3.62 [95% CI, 2.88–4.56]). CONCLUSIONS Influenza antiviral agents were underused in Canadian pediatric hospitals, including among children with high-risk chronic health conditions. Prescribing varied considerably across sites, increased over time, and was associated with patient and hospital-level characteristics. Multifaceted hospital-based interventions are warranted to strengthen adherence to influenza treatment guidelines and antimicrobial stewardship practices.

Objective Dolutegravir is recommended worldwide as a first-line antiretroviral therapy (ART) for individuals living with HIV. A recent study reported increased rates of neural tube defects in infants of dolutegravir-treated women. This study examined rates of congenital anomalies in infants born to women living with HIV (WLWH) in Canada. Design The Canadian Perinatal HIV Surveillance Programme captures surveillance data on pregnant WLWH and their babies and was analysed to examine the incidence of congenital anomalies. Setting Paediatric HIV clinics. Population Live-born infants born in Canada to WLWH between 2007 and 2017. Methods Data on mother-infant pairs, including maternal ART use at conception and during pregnancy, are collected by participating sites. Main outcome measures Congenital anomalies. Results Of the 2423 WLWH, 85 (3.5%, 95% CI 2.85-4.36%) had non-chromosomal congenital anomalies. There was no evidence of a significant difference in rates of congenital anomalies between women who were on ART in their first trimester (3.9%, CI 1.7-7.6%) or later in the pregnancy (3.9%, 95% CI 2.6-5.6%). Four of the 80 (5.0%, 95% CI 1.4-12.3%) neonates born to WLWH on dolutegravir during the first trimester had congenital anomalies, none were neural tube defects (95% CI 0.00-3.10%). Conclusion Despite recent evidence raising a safety concern, this analysis found no signal for increased congenital anomalies. Tweetable abstract Five percent of the infants of Canadian women living with HIV on dolutegravir at conception had congenital anomalies; none had neural tube defects.

Background The Canadian National Advisory Committee on Immunization recommends universal vaccination against pertussis in pregnancy. We assessed the cost-effectiveness of vaccination with tetanus-diphtheria-acellular pertussis (Tdap) vaccine in pregnancy in Canada. Methods We conducted a cost-utility analysis comparing a vaccination program to no program corresponding with the 2017 Canadian guideline for economic evaluation from the Canadian Agency for Drugs and Technologies in Health. We developed 2 models - part decision tree, part Markov model - to estimate the long-term cost and quality-adjusted life-years (QALYs) for pregnant women and their infants. We obtained epidemiologic data from 2006 to 2015, and derived costs and utility values from relevant sources. Results were reported in 2019 Canadian dollars. We obtained expected values through probabilistic analysis, with methodologic and structural uncertainty assessed through scenario analyses. The analysis adopted an acquisition price of Tdap vaccine of $12.50, with scenario analysis conducted to identify the threshold price for vaccination to be cost-effective. Results In the base-case scenario, for every 1000 pregnant women vaccinated, the program would lead to a gain of 0.3 QALYs, occurring solely in infants, at an increased total cost of $12 987, or $44 301 per QALY gained. Based on a threshold of $50 000 per QALY gained, vaccination would have been cost-effective in 6 of the 10 years included in the model (range of incremental costs $20 463-$100 348 per QALY gained). The threshold cost for Tdap vaccine to be cost-effective over the 10-year horizon was $14.03. Interpretation Based on a threshold of $50 000 per QALY gained, vaccination against pertussis in pregnancy would be cost-effective if the acquisition cost per vaccine were $14.03 or less. Province- and territory-specific analyses should be done to inform local decision-making.

Background:: HIV transmission during pregnancy and breastfeeding among serodiscordant heterosexual couples represents an ongoing barrier to the elimination of vertical transmission of HIV-1 infection in Canada. Objective:: To report a case of vertical HIV transmission during breastfeeding and examine the prevalence of risk factors for HIV transmission in the pregnancy and postpartum periods among serodiscordant couples where the male partner is HIV positive and female partner HIV negative. Methods:: Case report and retrospective chart review of HIV-serodiscordant pregnant couples over an eight-year period in Edmonton, Canada. Results:: We report a case of maternal primary HIV infection during the postpartum period and vertical transmission to a nursing infant that went undetected until the infant presented with AIDS. We also report a series of 41 serodiscordant pregnant couples identified by our public health nurse between 2008 and 2016. Among HIV-infected male partners, 20 (49%) had a detectable viral load (VL) during their partner’s pregnancy and during breastfeeding, with median peak VL 4,700 copies/mL (range 49-120,000) and 5,100 copies/mL (range 40-120,000) during pregnancy and breastfeeding, respectively. None of the female partners seroconverted during pregnancy, but three seroconverted at 1.8, 2.4, and 6.9 years after delivery. No vertical transmission occurred. Conclusion:: Despite concerted attempts to minimize HIV transmission during pregnancy and breastfeeding in our well-resourced setting, residual transmission risk remains due to non-suppressed viral load within many HIV-serodiscordant pregnant couples.

Sentinel surveillance of acute hospitalisations in response to infectious disease emergencies such as the 2009 influenza A(H1N1)pdm09 pandemic is well described, but recognition of its potential to supplement routine public health surveillance and provide scalability for emergency responses has been limited. We summarise the achievements of two national paediatric hospital surveillance networks relevant to vaccine programmes and emerging infectious diseases in Canada (Canadian Immunization Monitoring Program Active; IMPACT from 1991) and Australia (Paediatric Active Enhanced Disease Surveillance; PAEDS from 2007) and discuss opportunities and challenges in applying their model to other contexts. Both networks were established to enhance capacity to measure vaccine preventable disease burden, vaccine programme impact, and safety, with their scope occasionally being increased with emerging infectious diseases’ surveillance. Their active surveillance has increased data accuracy and utility for syndromic conditions (e.g. encephalitis), pathogen-specific diseases (e.g. pertussis, rotavirus, influenza), and adverse events following immunisation (e.g. febrile seizure), enabled correlation of biological specimens with clinical context and supported responses to emerging infections (e.g. pandemic influenza, parechovirus, COVID-19). The demonstrated long-term value of continuous, rather than incident-related, operation of these networks in strengthening routine surveillance, bridging research gaps, and providing scalable public health response, supports their applicability to other countries.

Respiratory syncytial virus (RSV) can cause severe disease in infants and older adults. Various vaccine candidates are in development and may become authorized for use in Canada within the next 2-5 years. The Public Health Agency of Canada sought to enhance preparedness for RSV vaccine and passive immunization candidates by organizing an expert retreat to identify knowledge gaps in surveillance and research and development in the context of provincial and territorial RSV public health priorities. We determined that RSV candidate vaccines in development directly address four out of five identified public health priorities, and identified remaining data gaps around vaccine efficacy and effectiveness. We determined that limited or sufficient surveillance data is available to support decision-making for four out of five RSV public health priorities and identified data gaps for several key populations: (i) for RSV cases under 17 years of age, gaps remain for denominator data to calculate incidence and data on medically attended outpatient visits; (ii) for RSV cases in Indigenous and remote communities, gaps remain for data on incidence, prevalence, specific risk factors, feasibility and acceptability; and (iii) for RSV cases in older adults, gaps remain for data on incidence. This process demonstrated the feasibility of, and stakeholder support for, gap analyses in surveillance data to support decisions about prospective vaccines and immune products.

Background There is no uniform guideline for postchemotherapy vaccination of children with acute lymphoblastic leukemia (ALL). We evaluated waning immunity to 14 pneumococcal serotypes, pertussis toxin (PT), tetanus toxoid (TT) and varicella, and immunogenicity of postchemotherapy diphtheria, tetanus, pertussis, hepatitis B, polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) and pneumococcal vaccination among previously vaccinated children treated for ALL. Methods This was a multicenter trial of children with ALL enrolled 4–12 months postchemotherapy completion. Exclusion criteria included: infant ALL, relapsed ALL, and stem cell transplant recipients. Immunocompetent children were recruited as controls. Postchemotherapy participants received DTaP-IPV-Hib and 13-valent pneumococcal conjugate vaccine (PCV13) concurrently, followed by 23-valent pneumococcal polysaccharide vaccine (PPV23) 2 months later. Serology was measured at baseline, 2 and 12 months postvaccination. Adverse events were captured via surveys. Results At enrollment, postchemotherapy participants (n = 74) were less likely than controls (n = 78) to be age-appropriately immunized with DTaP (41% vs 89%, P, In this multicenter trial, previously vaccinated children treated for acute lymphoblastic leukemia had lower antibody levels than controls to Streptococcus pneumoniae, tetanus toxoid, pertussis toxin, and varicella. Booster vaccination was immunogenic and well tolerated, suggesting benefit of systematic revaccination postchemotherapy.

Background TrumenbaTM, a bivalent, factor-H binding protein meningococcal serogroup B (MenB-fHBP) vaccine was authorized for use in Canada in October 2017 for the prevention of invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup B in individuals 10-25 years of age. The National Advisory Committee on Immunization (NACI) provides recommendations regarding the use of meningococcal vaccines to the Public Health Agency of Canada. Objective To summarize NACI recommendations regarding the use of MenB-fHBP vaccine in Canada. Methods The NACI Meningococcal Disease Working Group developed a predefined search strategy to identify all eligible studies, assessed the quality of these studies, and summarized and analyzed the findings. According to the NACI evidence-based process, the working group then proposed recommendations and identified the grade of evidence that supported them. In light of the evidence, the recommendations were then considered and approved by NACI. Results The two serogroup B meningococcal vaccines currently authorized for use in Canada are not interchangeable as they contain different antigens and there are no published studies on the immunogenicity resulting from a vaccination series combining the two products. Following the review of evidence, NACI recommends that MenB-fHBP vaccine may be considered as an option for use in individuals 10 years of age and older in situations when a serogroup B meningococcal vaccine should be offered: 1) during serogroup B meningococcal disease outbreaks or with the emergence of hyperendemic N. meningitidis strains that are predicted to be susceptible to the vaccine; 2) for individuals who are close contacts with a case of invasive meningococcal disease caused by serogroup B N. meningitidis; 3) for individuals with underlying medical conditions that would put them at higher risk of meningococcal disease than the general population; or 4) for individuals at higher risk of exposure to serogroup B meningococcal isolates than the general population. NACI also recommends that MenB-fHBP vaccine may be considered as an option for individuals 10-25 years of age who are not at higher risk of meningococcal disease than the general population, but who wish to reduce their risk of invasive serogroup B meningococcal disease. Conclusion NACI recommends immunization against serogroup B IMD for all individuals who are at a higher risk of disease due to an underlying medical condition or an increased risk of exposure. In addition to providing guidance to public health decision-makers (i.e. provinces/territories making decisions for publicly-funded immunization programs), these NACI recommendations provide information to individuals, vaccine providers and organizations about vaccines that may not currently be included in publicly funded immunization programs. NACI continues to recommend against the use of the serogroup B vaccines in routine universal immunization programs in Canada at this time.

Background Recent increases in pertussis morbidity and mortality rates among young infants have led to a recommendation in some countries for vaccination against pertussis during pregnancy. Having data on the burden of pediatric pertussis in a large population over time is important for establishing the true burden of disease in the acellular pertussis (aP) vaccine era. Here, we describe age-specific epidemiology and morbidity and mortality rates in children hospitalized with pertussis over 17 years across Canada in the aP vaccine era. Methods Patients aged ≤16 years who were admitted to 1 of 12 pediatric tertiary-care hospitals across Canada between 1999 and 2015 with confirmed (laboratory-confirmed or epidemiologically linked) or probable (clinically diagnosed) pertussis were included. Results Overall, 1402 patients with pertussis were included. Infants aged, Infants aged

BACKGROUND: Vertical HIV transmission has declined in Canada, but missed opportunities for prevention continue to occur. We sought to determine the adequacy, and changes over time in adequacy, of uptake of maternal and neonatal antiretroviral therapy for the prevention of vertical HIV transmission, and to determine the vertical transmission rate over time and according to adequacy of antenatal antiretroviral therapy during the combination antiretroviral therapy era in Canada. METHODS: The Canadian Perinatal HIV Surveillance Program collects data annually through retrospective chart review concerning HIV-infected women and their infants. We determined receipt of adequate antiretroviral treatment (antenatal combination antiretroviral treatment for ≥ 4 wk, intrapartum intravenous zidovudine treatment and 4-6 wk of infant oral zidovudine treatment) and predictors of inadequate antenatal combination antiretroviral therapy (none or < 4 wk) in Canada in 1997-2016. RESULTS: We identified 3785 mother-infant pairs. Uptake of 4 weeks or more of antenatal combination antiretroviral therapy increased over time across all provinces/territories and regardless of maternal race/ethnicity or risk category (p < 0.001). During 2011-2016, 92 women (6.5%) received no or less than 4 weeks of antenatal combination antiretroviral therapy, 146 women (10.7%) received no intrapartum zidovudine treatment, and 43 infants (3.1%) received less than 4 weeks of zidovudine treatment. In multivariate analysis restricted to 2011-2016, higher uptake of adequate antenatal combination antiretroviral therapy was seen among black women than among Indigenous (odds ratio [OR] 2.99, 95% confidence interval [CI] 1.23-7.26) or white (OR 1.87, 95% CI 0.99-1.27) women and in British Columbia/Yukon Territory than in Alberta (OR 3.31, 95% CI 1.06-10.32), Ontario (OR 3.16, 95% CI 1.08-9.26) or Quebec (OR 3.44, 95% CI 1.09-10.84). Among the 14 vertical HIV transmission events during 2011-2016 (vertical transmission rate 1.0%), maternal HIV infection was diagnosed before the onset of labour in 5 cases, and only 2 women received adequate antenatal combination antiretroviral therapy. INTERPRETATION: Efforts to improve timely access to care, HIV screening and treatment for all women, combined with enhanced resources targeting populations at increased risk for HIV infection, will be needed if vertical HIV transmission is to be eliminated in Canada.

Background Influenza is a respiratory infection caused primarily by influenza A and B viruses. Vaccination is the most effective way to prevent influenza and its complications. The National Advisory Committee on Immunization (NACI) provides recommendations regarding seasonal influenza vaccines annually to the Public Health Agency of Canada (PHAC). Objective To summarize the NACI recommendations regarding the use of seasonal influenza vaccines for the 2017-2018 influenza season. Methods Annual influenza vaccine recommendations are developed by NACI's Influenza Working Group for consideration and approval by NACI, based on NACI's evidence-based process for developing recommendations. The recommendations include a consideration of the burden of influenza illness and the target populations for vaccination; efficacy and effectiveness, immunogenicity and safety of influenza vaccines; vaccine schedules; and other aspects of influenza immunization. These recommendations are published annually on the Agency's website in the NACI Advisory Committee Statement: Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine (the Statement). Results The annual statement has been updated for the 2017-2018 influenza season to incorporate recommendations for the use of live attenuated influenza vaccine (LAIV) that were contained in two addenda published after the 2016-2017 statement. These recommendations were 1) that egg-allergic individuals may be vaccinated against influenza using the low ovalbumin-containing LAIV licensed for use in Canada and 2) to continue to recommend the use of LAIV in children and adolescents 2-17 years of age, but to remove the preferential recommendation for its use. Conclusion NACI continues to recommend annual influenza vaccination for all individuals aged six months and older, with particular focus on people at high risk of influenza-related complications or hospitalization, people capable of transmitting influenza to those at high risk, and others as indicated.

Background Invasive meningococcal disease caused by Neisseria meningitidis serogroup B (MenB) remains a health risk in Canada and globally. Two MenB vaccines are now approved for use. An understanding of the genotype of Canadian strains and the potential strain coverage conferred by the MenB-FHbp vaccine is needed to inform immunization policies. Methods Serogroup B Neisseria meningitidis strains responsible for meningococcal disease in Canada from 2006 to 2012 were collected as part of the Canadian Immunization Monitoring Program Active surveillance network. Genotypic analysis was done on MenB isolates from 2006 to 2012 with determination of fHbp surface expression for a subset of isolates: those occurring from 2010 to 2012. Results Two clonal complexes (cc269 and cc41/44) were observed in 68.8% of the 276 isolates. A total of 50 different fHbp peptides were identified among isolates from 2006 to 2012. Surface expression of fHbp was detected on 95% of MenB isolates from 2010 to 2012 and 91% of isolates expressed fHbp at levels that are predicted to be susceptible to the bactericidal immune response elicited by the MenB-FHbp vaccine. Some regional differences were observed, particularly in isolates from British Columbia and Quebec. Conclusion The majority of MenB isolates responsible for meningococcal disease in Canada expressed fHbp at levels predicted to be sufficient for complement mediated bactericidal activity in the presence of MenB-FHbp induced serum antibodies.

BACKGROUND: There are many different influenza vaccines authorized for use in Canada and new evidence on influenza and vaccines is emerging all the time. The National Advisory Committee on Immunization (NACI) provides recommendations annually regarding seasonal influenza vaccines to the Public Health Agency of Canada (PHAC). OBJECTIVE: To summarize the NACI recommendations regarding the use of seasonal influenza vaccines for the 2018–2019 influenza season in light of two NACI reviews conducted on 1) the risk of serious influenza-related complications in children and adults with neurologic and neurodevelopment conditions and 2) the efficacy/effectiveness of high-dose and adjuvanted inactivated influenza vaccines in persons 65 years of age and older. METHODS: For both topics, NACI’s Influenza Working Group developed a predefined search strategy to identify all eligible studies, assessed their quality, summarized and analyzed the findings, proposed recommendations and identified the Grade of evidence that supported them. In light of the evidence, the recommendations were then considered and approved by NACI. RESULTS: NACI concludes there is fair evidence to recommend that children and adults with neurologic and neurodevelopment conditions are groups for whom influenza immunization is particularly recommended (Evidence Grade B recommendation). On choosing influenza vaccines for persons 65 years of age and older, at a programmatic level, NACI recommends that any of the four influenza vaccines available for use should be used. There is insufficient evidence to make a comparative recommendation on the use of these vaccines at a programmatic level (Grade I). At an individual level, NACI recommends that high-dose trivalent inactivated influenza vaccine (TIV) should be offered over standard-dose TIV to persons 65 years of age and older (Grade A). There is insufficient evidence to make comparative recommendations on the use of MF59-adjuvanted TIV and quadrivalent inactivated influenza vaccine over standard-dose TIV (Grade I). CONCLUSION: NACI continues to recommend annual influenza vaccination for all individuals aged six months and older, with particular focus on people at high risk of influenza-related complications or hospitalization, people capable of transmitting influenza to those at high risk, people who provide essential community services and people in direct contact during culling operations with poultry infected with avian influenza.

BACKGROUND For patients who have experienced adverse events following immunization (AEFI) or who have specific medical conditions, there is limited evidence regarding the best approach to immunization. The Special Immunization Clinics (SICs) Network was established to standardize patient management and assess outcomes after reimmunization. The study objective was to describe the first 2 years of the network's implementation. METHODS Twelve SICs were established across Canada by infectious diseases specialists and allergists. Inclusion criteria were as follows: local reaction ≥ 10 cm, allergic symptoms < 24 hours postimmunization, neurologic symptoms and other AEFI or medical conditions of concern. Eligible patients underwent a standardized evaluation, causality assessment was performed, immunization recommendations were made by expert physicians and patients were followed up to capture AEFI. After individual consent, data were transferred to a central database for analysis. RESULTS From June 2013 to May 2015, 151 patients were enrolled. Most were referred for prior AEFI (132/151, 87%): 42 (32%) for allergic-like reactions, 31 (23%) for injection-site reactions, 20 (15%) for neurologic symptoms and 39 (30%) for other systemic symptoms. Nineteen patients (13%) were seen for underlying conditions that complicated immunization. Reimmunization was recommended for 109 patients, 60 of whom (55%) were immunized and followed up. Eleven patients (18%) experienced recurrence of their AEFI; none were serious (eg, resulting in hospitalization, permanent disability or death). CONCLUSIONS The most frequent reasons for referral to a SIC were allergic-like events and injection site reactions. Reimmunization was safe in most patients. Larger studies are needed to determine outcomes for specific types of AEFI.

There are no Canadian immunization guidelines for children treated for malignancy. Guidelines do exist for patients who underwent hematopoietic stem cell transplant (HSCT), but they provide broad timeframes for initiating vaccination; there is no standard schedule. The optimal approach to immunization in these populations is unclear. We sought to describe immunization practices at Canadian Pediatric Hematology/Oncology centers. A 43-item online questionnaire was distributed to the 16 programs in the C(17) research network of pediatric hematology/oncology centers to capture information on timing and criteria for immunization of patients with acute lymphocytic leukemia (ALL) and those who have undergone HSCT. At each center, 1-2 physicians or pharmacists completed the survey to reflect center-wide immunization practices. Responses were received from 11/16 (69%) programs; 11 respondents reported on practices for patients with ALL and 9 reported on practices for patients who are post-HSCT. In 5/11 ALL programs (45%) re-immunization is recommended routinely after chemotherapy, starting 3-6 months post-chemotherapy. In HSCT programs, timing of pneumococcal conjugate vaccination (PCV) varied from 3 months post-HSCT (4 programs) to 12 months post-HSCT (4 programs). Live vaccines were administered 24 months post-HSCT in 8/9 programs. All HSCT programs considered graft-versus-host-disease and 7 considered discontinuation of immunosuppression in immunization decisions. Pediatric hematology/oncology programs were divided in regards to re-immunization of patients with ALL post-chemotherapy. After HSCT, timing of PCV administration varied, with 4 programs initiating immunization later than Canadian guidelines recommend (3-9 months post-HSCT). These findings suggest a need to standardize immunization practices in these populations.

Congenital cytomegalovirus infection (cCMV) is the most common congenital infection, occurring in approximately 0.5% of live births. Most infected newborns are asymptomatic, but up to 20% develop sensorineural hearing loss or other permanent neurologic sequelae. The presentation of newborns with symptomatic cCMV is highly variable, and the infection is usually not diagnosed in the absence of a screening program. Newborn cCMV screening programs are estimated to be beneficial and cost-effective, and are increasingly being implemented. Diagnosis requires direct detection of virus in a sample obtained before 3 weeks of life, and is best performed by polymerase chain reaction (PCR) of saliva or urine, either of which is more sensitive than dried blood spot. Antiviral treatment of selected newborns with cCMV-related disease appears to improve hearing and neurocognitive outcomes. All infected infants should be evaluated promptly to determine appropriate therapy, and receive close audiologic and developmental follow-up.

More women with autoimmune and inflammatory conditions are being treated with monoclonal antibody biologics (mAbs) during their pregnancy, to maintain clinical remission. The use of anti-tumor necrosis factor alpha agents in pregnancy appears to be safe but less is known regarding other mAbs, such as anti-integrins and anti-cytokine agents. There are currently no comprehensive guidelines on how to manage the exposed infants. Areas covered: We review recent literature to assess the impact of mAbs on birth and early infant outcomes, including what is currently known about maternal and infant drug levels at birth and drug clearance in the infant. We describe the potential risks of infections and reported hematological and immunological effects of antenatal mAbs exposure on the infant and provide guidance on the management of the exposed infant. Expert opinion: Exposed infants should be monitored closely. Certain mAb exposures require specific testing and management. Safety monitoring should be done in a multidisciplinary approach and should include pediatric care providers. The current clinical experience with anti-tumor necrosis factor agents in pregnancy cannot be extrapolated to other mAbs. Long-term observational studies and a multicenter international registry are needed to better appreciate the impact of exposure, especially to newer mAbs.

For almost 25 years the Canadian Immunization Monitoring Program, ACTive (IMPACT) has been conducting active surveillance for severe adverse events following immunization (AEFIs) and vaccine-preventable diseases in children. The network, which consists of volunteer paediatric infectious diseases investigators at 12 tertiary care paediatric hospitals, is an important component of Canada’s AEFI monitoring. The network employs nurses at each of the sites to search for and report possible AEFIs to local, provincial and national public health authorities. The active nature of the surveillance ensures a high level of vigilance for severe AEFIs in children.

BACKGROUND The Canadian Immunization Monitoring Program ACTive (IMPACT) conducts active surveillance for varicella-related hospitalizations in 12 paediatric tertiary care centres, starting Apr 1999. OBJECTIVES This study was to determine the hospitalization trends in relation to vaccine program introduction in the provinces, between 2000 and 2015. DESIGN/METHODS Demographic data of varicella cases from the 12 IMPACT centers were analysed. The cases were subdivided into three groups (A, B and C), combining provinces with approximately the same time periods at introduction of 1-dose and 2-dose vaccination programs (see results). RESULTS The mean number of hospitalizations per year declined during the 1-dose and 2-dose eras in each group of provinces, as follows: CONCLUSION Varicella hospitalizations declined by 63–77% but reached a plateau during the 1-dose vaccine era. There was a further decline to 81–89% of baseline in the two groups which instituted 2-dose vaccine programs in 2011–12, but too early to document any further decline in Group C, the provinces which initiated 2-dose programs in 2014–16. Introduction of 2-dose programs appear to have provided further benefit, after 1-dose programs in Canada.

We studied the epidemiology of Haemophilus influenzae type b infections among children with cancer admitted to Canadian pediatric hospitals. From 1991 to 2014, 13 cases among children with cancer were identified through active surveillance. Average age was 6.7 years. Six of 7 cases eligible for infant immunization were age-appropriately immunized (vaccine failures). Children with cancer may benefit from booster Hib immunization.

Background Immunization of pregnant women with tetanus-diphtheria-acellular pertussis vaccine (Tdap) provides protection against pertussis to the newborn infant. Methods In a randomized, controlled, observer-blind, multicenter clinical trial, we measured the safety and immunogenicity of Tdap during pregnancy and the effect on the infant's immune response to primary vaccination at 2, 4, and 6 months and booster vaccination at 12 months of age. A total of 273 women received either Tdap or tetanus-diphtheria (Td) vaccine in the third trimester and provided information for the safety analysis and samples for the immunogenicity analyses; 261 infants provided serum for the immunogenicity analyses. Results Rates of adverse events were similar in both groups. Infants of Tdap recipients had cord blood levels that were 21% higher than maternal levels for pertussis toxoid (PT), 13% higher for filamentous hemagglutinin (FHA), 4% higher for pertactin (PRN), and 7% higher for fimbriae (FIM). These infants had significantly higher PT antibody levels at birth and at 2 months and significantly higher FHA, PRN, and FIM antibodies at birth and 2 and 4 months, but significantly lower PT and FHA antibody levels at 6 and 7 months and significantly lower PRN and FIM antibody levels at 7 months than infants whose mothers received Td. Differences persisted prebooster at 12 months for all antigens and postbooster 1 month later for PT, FHA, and FIM. Conclusions This study demonstrated that Tdap during pregnancy results in higher levels of antibodies early in infancy but lower levels after the primary vaccine series. Clinical trials registration NCT00553228.

BACKGROUND: Before 2001, the incidence of invasive meningococcal disease (IMD) in Canada was 1.0 per 100 000 per year, with 40% of cases caused by serogroup C organisms. During 2001-2005 all provinces introduced the meningococcal serogroup C conjugate vaccine (MCCV) into their routine infant immunization schedule. METHODS: Active, prospective, population-based surveillance of IMD in children and adults was conducted by the Canadian Immunization Monitoring Program, ACTive (IMPACT) during 2002-2012. Inclusion criteria were admission to hospital and identification of Neisseria meningitidis from a sterile site. Incidence was estimated using population census data from Statistics Canada. RESULTS: Prior to MCCV introduction, serogroup C disease incidence was 0.07-0.25 per 100 000 per year depending on the province. Following vaccine introduction, serogroup C disease decreased to

BACKGROUND: The extent to which influenza A and B infection differs remains uncertain. METHODS: Using active surveillance data from the Canadian Immunization Monitoring Program Active at 12 pediatric hospitals, we compared clinical characteristics and outcomes of children ≤16 years admitted with laboratory-confirmed influenza B or seasonal influenza A. We also examined factors associated with ICU admission in children hospitalized with influenza B. RESULTS: Over 8 nonpandemic influenza seasons (2004-2013), we identified 1510 influenza B and 2645 influenza A cases; median ages were 3.9 and 2.0 years, respectively (P < .0001). Compared with influenza A patients, influenza B patients were more likely to have a vaccine-indicated condition (odds ratio [OR] = 1.30; 95% confidence interval [CI] = 1.14–1.47). Symptoms more often associated with influenza B were headache, abdominal pain, and myalgia (P < .0001 for all symptoms after adjustment for age and health status). The proportion of deaths attributable to influenza was significantly greater for influenza B (1.1%) than influenza A (0.4%); adjusted for age and health status, OR was 2.65 (95% CI = 1.18–5.94). A similar adjusted OR was obtained for all-cause mortality (OR = 2.95; 95% CI = 1.34–6.49). Among healthy children with influenza B, age ≥10 years (relative to CONCLUSIONS: Mortality associated with pediatric influenza B infection was greater than that of influenza A. Among healthy children hosptialized with influenza B, those 10 years and older had a significant risk of ICU admission.

BACKGROUND: The extent to which pandemic H1N1 influenza (pH1N1) differed from seasonal influenza remains uncertain. METHODS: By using active surveillance data collected by the Immunization Monitoring Program, Active at 12 Canadian pediatric hospitals, we compared characteristics of hospitalized children with pH1N1 with those with seasonal influenza A. We compared demographics, underlying health status, ICU admission, and mortality during both pandemic waves versus the 2004/2005 through the 2008/2009 seasons; influenza-related complications and hospitalization duration during pH1N1 wave 1 versus the 2004/2005 through the 2008/2009 seasons; and presenting signs and symptoms during both pH1N1 waves versus the 2006/2007 through the 2008/2009 seasons. RESULTS: We identified 1265 pH1N1 cases (351 in wave 1, 914 in wave 2) and 1319 seasonal influenza A cases (816 from 2006/2007 through 2008/2009). Median ages were 4.8 (pH1N1) and 1.7 years (seasonal influenza A); P < .0001. Preexisting asthma was overrepresented in pH1N1 relative to seasonal influenza A (13.8% vs 5.5%; adjusted P < .0001). Symptoms more often associated with pH1N1 wave 1 versus seasonal influenza A were cough, headache, and gastrointestinal symptoms (adjusted P < .01 for each symptom). pH1N1 wave 1 cases were more likely to have radiologically confirmed pneumonia (adjusted odds ratio = 2.1; 95% confidence interval = 1.1–3.8) and longer median length of hospital stay (4 vs 3 days; adjusted P = .003) than seasonal influenza A. Proportions of children requiring intensive care and deaths in both pH1N1 waves (14.6% and 0.6%, respectively) were not significantly different from the seasonal influenza A group (12.7% and 0.5%, respectively). CONCLUSIONS: pH1N1 in children differed from seasonal influenza A in risk factors, clinical presentation, and length of hospital stay, but not ICU admission or mortality.

Rotavirus is the main cause of gastroenteritis in Canadian children younger than five years of age, resulting in significant morbidity and cost. The present study provides evidence on the cost effectiveness of two alternative rotavirus vaccinations (RotaTeq [Merck Frosst Canada Ltd, Canada] and Rotarix [GlaxoSmithKline, Canada]) available in Canada.Analysis was conducted through a Markov model that followed a cohort of children from birth to five years of age. Analysis used pertinent data on the natural history of rotavirus and the effects of vaccination. Estimates of heath care costs for children requiring hospitalizations and emergency department visits were derived from the Canadian Immunization Monitoring Program, Active (IMPACT) surveillance, emergency department studies, as well as other Canadian studies. The model estimated the effect of vaccination on costs and quality-adjusted life years (QALYs).The incremental cost per QALY gained from the health care system perspective was $122,000 for RotaTeq and $108,000 for Rotarix. From the societal perspective, both vaccination strategies were dominant - both cost saving and more effective. The cost-effectiveness of vaccination is dependent on the mode of administration, the perspective adopted and the cost of the vaccine.From a societal perspective, a universal vaccination program against rotavirus will be both cost saving and more effective than no vaccination. Becasue the majority of rotavirus infections do not require emergency department visits or hospital admission, from a health care system perspective, a program would not be considered cost effective.Le rotavirus est la principale cause de gastroentérite chez les enfants canadiens de moins de cinq ans, ce qui s’associe à une morbidité et à des coûts considérables. La présente étude expose des données probantes sur le rapport coût-efficacité de deux vaccins contre le rotavirus (RotaTeq [Merck Frosst Canada Ltée, Canada] et Rotarix [GlaxoSmithKline, Canada]) offerts au Canada.Les chercheurs ont effectué l’analyse au moyen d’un modèle de Markov qui consistait à suivre une cohorte d’enfants entre la naissance et cinq ans. L’analyse faisait appel à des données pertinentes sur l’évolution naturelle du rotavirus et sur les effets de la vaccination. Les évaluations des coûts de santé à l’égard des enfants devant être hospitalisés et consulter à l’urgence étaient tirées de la surveillance du Programme canadien de surveillance active de l’immunisation (IMPACT), d’études des départements d’urgence et d’autres études canadiennes. Le modèle a permis d’évaluer l’effet de la vaccination sur les coûts et les années de vie ajustées en fonction de la qualité (AVAQ).Le coût incrémentiel par AVAQ épargné par le système de santé s’élevait à 122 000 $ à l’aide du vaccin RotaTeq et à 108 000 $ à l’aide du vaccin Rotarix. Sur le plan sociétal, les deux stratégies vaccinales étaient dominantes, c’est-à-dire qu’elles étaient à la fois rentables et plus efficaces. Le rapport coût-efficacité de la vaccination dépend du mode d’administration, de la perspective adoptée et du coût du vaccin.Sur le plan sociétal, un programme de vaccination universel contre le rotavirus sera à la fois rentable et plus efficace que l’absence de vaccination. Puisque la majorité des infections à rotavirus n’exigent pas de consultation à l’urgence ou d’hospitalisation, le programme ne serait pas rentable pour le système de santé.

Rotavirus infections are one of the most common hospital acquired infections in pediatric hospitals. Laboratory confirmed hospital acquired rotavirus infections from 12 pediatric hospitals in Canada were documented for a 3 year period, 2005-7. Overall, hospital acquired infections represented one quarter of all rotavirus hospitalizations for an annual rate of 0.45 per 1000 hospital days with a peak of 0.68 per 1,000 hospital days between December and May. Approximately 8% developed symptoms

The standard of care for the prevention of vertical transmission (VT) of HIV in Canada and other developed countries includes routine prenatal HIV testing for all pregnant women, and for those testing positive: antepartum combination antiretroviral therapy (cART); intrapartum intravenous zidovudine; six weeks of postnatal oral zidovudine to the infant; and exclusive formula feeding of the infant. With these interventions, the rate of VT has been reduced from 25% to 40%, to 4 weeks before delivery. The purpose of the present article is to highlight recent changes in management guidelines and important caveats to these changes with regard to prevention of VT in the Canadian context. There is a global trend to replace the use of the previous conventional terminology of ‘mother-to-child transmission’ with ‘vertical transmission’ or ‘perinatal transmission’ to remove implications of blame from the mother. In the present article, ‘vertical transmission’ is used throughout. HIV testing during pregnancy HIV testing is recommended for all pregnant women in Canada, with appropriate pre- and post-test counselling. Women whose HIV status is unknown at the time of delivery should undergo rapid HIV antibody testing. For women at increased risk for HIV infection (eg, intravenous drug use, commercial sex work, frequent unprotected intercourse with multiple partners, HIV-negative woman of a serodiscordant couple) who test negative early in pregnancy, repeat testing late in pregnancy (beginning of the third trimester) and at delivery is strongly encouraged. When such women present in labour, advice regarding maternal HIV diagnosis and management should be sought from obstetric and adult HIV experts on an urgent basis; similarly, pediatric HIV experts should be consulted regarding infant management in such situations. Women living with HIV, either previously diagnosed or identified during pregnancy, should be followed by a specialist with expertise in the management of HIV during pregnancy, treated with cART and monitored for viral suppression. Prelabour elective Cesarean section delivery should be planned for those not on cART and/or anticipated or documented to have inadequate viral suppression near delivery (viral load >1000 copies/mL). For women who were previously diagnosed with HIV in whom viral load is not documented to be fully suppressed in the four weeks preceding onset of labour and for women diagnosed with HIV infection at the time of labour, urgent consultation with adult and pediatric HIV experts and an obstetrician with expertise in the management of HIV is essential. Recommendation 1: Pediatricians and other health care providers involved in the care of HIV-infected pregnant women and their children should advocate for universal HIV testing of all pregnant women with appropriate pre- and post-test counselling so that appropriate preventive measures can be implemented in a timely manner. When this fails, testing of the mother at delivery, or of the infant if maternal testing is not possible, should be ensured. Ideally, no infant should be discharged from hospital without the HIV status of the mother being known. Pediatricians and family physicians who perform routine neonatal examinations should verify that the HIV status of the mother or child is known and documented. Recommendation 2: Urgent consultation with an obstetrician with HIV expertise and an adult HIV expert is recommended for diagnosis and management of women deemed to be at high risk for HIV infection with unknown status at the time of labour. Similarly, a pediatric HIV expert should be consulted regarding infant management in such situations.

We describe community-acquired rotavirus illness in 1359 children hospitalized at 12 centers in Canada between January 2005 and December 2007. The median age was 1.5 years. Almost half (48.6%) had significant dehydration, almost one-fifth (19%) had clinical sepsis and 7% had seizures at presentation. The median hospital stay was 3.4 days. Severe clinical presentations are less commonly described in surveillance programs.