Factors associated with intention for revaccination among patients with adverse events following immunization.

Objectives: Individuals and healthcare providers may be uncertain about the safety of revaccination after an adverse event following immunization (AEFI). We identified factors associated with physician recommendation for revaccination and participant intention to be revaccinated among patients with adverse events following immunization (AEFIs) assessed in the Canadian Special Immunization Clinic (SIC) Network from 2013 to 2019.

Methods: This prospective observational study included patients assessed in the Canadian Special Immunization Clinic Network from 2013 to 2019 for an AEFI who required additional doses of the vaccine temporally associated with their AEFI.

Revaccination and Adverse Event Recurrence in Patients with Adverse Events following Immunization.

Objectives: 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.

Study Design: 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.

Antiviral Use in Canadian Children Hospitalized for Influenza.

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.

Pregnancy Among HIV-Serodiscordant Couples: Case Report of Vertical Transmission and Retrospective Case Series.

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.

Pertussis vaccination in pregnancy in Canada: a cost-utility analysis.

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.

Active surveillance of acute paediatric hospitalisations demonstrates the impact of vaccination programmes and informs vaccine policy in Canada and Australia.

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.

Overview of the respiratory syncytial virus vaccine candidate pipeline in Canada.

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.

Review of pediatric encephalitis and encephalopathy cases following immunization reported to the Canadian Immunization Monitoring Program Active (IMPACT) from 1992 to 2012.

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).

Gap analyses to assess Canadian readiness for respiratory syncytial virus vaccines: Report from an expert retreat.

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.

Summary of the NACI Statement on the Use of Bivalent Factor H Binding Protein Meningococcal Serogroup B (MenB-fHBP) Vaccine for the Prevention of Meningococcal B Disease.

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 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.

Waning Vaccine Immunity and Vaccination Responses in Children Treated for Acute Lymphoblastic Leukemia: A Canadian Immunization Research Network Study.

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.

Estimated susceptibility of Canadian meningococcal B isolates to a meningococcal serogroup B vaccine (MenB-FHbp).

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.

Challenges to achieving and maintaining viral suppression among children living with HIV.

Objectives: The objective of this study was to determine the time to, and durability of, viral suppression, among Canadian children living with HIV after initiation of combination antiretroviral therapy (cART).

Design: Prospective, multicenter Canadian cohort study (Early Pediatric Initiation Canada Child Cure Cohort), using both prospective and retrospectively collected data.

Methods: Kaplan-Meir survival estimates with Cox regression were used to determine the time to and risk factors for viral suppression, defined as two consecutive undetectable viral loads (<50 copies/ml) at least 30 days apart after initiation of cART.

From mother to baby: antenatal exposure to monoclonal antibody biologics.

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.

Burden of Children Hospitalized With Pertussis in Canada in the Acellular Pertussis Vaccine Era, 1999-2015.

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.

A Randomized Controlled Trial of the Safety and Immunogenicity of Tetanus, Diphtheria, and Acellular Pertussis Vaccine Immunization During Pregnancy and Subsequent Infant Immune Response.

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.

Missed opportunities for prevention of vertical HIV transmission in Canada, 1997-2016: a surveillance study.

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.

Diagnosis and management of infants with congenital cytomegalovirus infection.

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.

Invasive Haemophilus Influenzae Type B Infections in Children with Cancer in the Era of Infant HIB Immunization Programs (1991-2014): A Report From the Canadian Immunization Monitoring Program Active.

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.

Immunizing Patients With Adverse Events After Immunization and Potential Contraindications to Immunization: A Report From the Special Immunization Clinics Network.

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.

Hospitalization for Influenza A Versus B.

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.

Immunization practices in acute lymphocytic leukemia and post-hematopoietic stem cell transplant in Canadian Pediatric Hematology/Oncology centers.

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.

Safety of combination antiretroviral prophylaxis in high-risk HIV-exposed newborns: a retrospective review of the Canadian experience.

Introduction: The optimal management of infants born to HIV-positive mothers who are untreated or have detectable viral load prior to delivery remains controversial. Despite the increasing use of combination antiretroviral therapy (cART) for post-exposure prophylaxis (PEP) of neonates at high risk of HIV infection, there is little safety and pharmacokinetic data to support this approach. The objective of this study was to evaluate the safety and tolerability of cART for PEP in HIV-exposed neonates.