Karina Top

Karina Top
Dalhousie University | Dal · Departments of Pediatrics and Community Health & Epidemiology

MD, MS

About

92
Publications
12,560
Reads
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948
Citations
Additional affiliations
August 2011 - present
Dalhousie University
July 2008 - June 2011
Columbia University
July 2005 - June 2008
Dalhousie University
Position
  • Pediatric Resident
Education
September 2011 - May 2013
Columbia University
Field of study
  • Epidemiology
August 2001 - May 2005
Dalhousie University
Field of study
  • Medicine
September 1998 - June 2001
University of Toronto
Field of study
  • Immunology

Publications

Publications (92)
Article
Full-text available
Background and objectives Safety and effectiveness concerns may preclude physicians from recommending vaccination in mild/moderate inborn errors of immunity (IEI). This study describes attitudes and practices regarding vaccination among physicians who care for patients with mild/moderate B cell or mild/moderate combined immunodeficiencies (CID) and...
Article
Background: The gaps in clinical trial evidence about vaccination in pregnancy have serious implications for health care worker and public misunderstandings. Contradictions between National Immunization Technical Advisory Group (NITAG) recommendations and regulatory product labeling information contribute to misinformation about vaccine safety and...
Article
Within two years, novel SARS-CoV-2 vaccines have been developed, rigorously evaluated in large phase 3 trials, and administered to over 5 billion individuals globally. However, adverse events of special interest (AESIs) have been described post-implementation, including myocarditis after mRNA vaccines and thrombosis with thrombocytopenia syndrome (...
Article
Background: Post-licensure adverse events following immunization (AEFI) surveillance is conducted to monitor vaccine safety, such as identifying batch/brand issues and rare reactions, which consequently improves community confidence. The integration of technology has been proposed to improve AEFI surveillance, however, there is an absence of descr...
Preprint
Background Paediatric inflammatory multisystem syndrome (PIMS) is a rare but serious condition temporally associated with SARS-CoV-2 infection. Using the Canadian Paediatric Surveillance Program (CPSP), a national surveillance system, we aimed to 1) study the impact of SARS-CoV-2 linkage on clinical and laboratory characteristics, and outcomes in h...
Preprint
Purpose: The objective of this study was to describe the clinical course and outcomes in children with technology-dependence (TD) hospitalized with SARS-CoV-2 infection.Methods: Seventeen pediatric hospitals (15 Canadian and one each in Iran and Costa Rica) included children up to 17 years of age admitted February 1, 2020, through May 31, 2021, wit...
Preprint
Background Children living with chronic comorbid conditions are at increased risk for severe COVID-19, though there is limited evidence regarding the risks associated with specific conditions and which children may benefit from targeted COVID-19 therapies. The objective of this study was to identify factors associated with severe disease among hosp...
Article
Full-text available
Background: The COVID-19 pandemic resulted in unprecedented implementation of wide-ranging public health measures globally. During the pandemic, dramatic decreases in seasonal influenza virus detection have been reported worldwide. Information on the impact on paediatric influenza-related hospitalisations is limited. We describe influenza-related h...
Article
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Age is the most important determinant of COVID-19 severity. Infectious disease severity by age is typically J-shaped, with infants and the elderly carrying a high burden of disease. We report on the comparative disease severity between infants and older children in a multicenter retrospective cohort study of children 0 to 17 years old admitted for...
Preprint
Background Pregnant individuals have been receiving COVID-19 vaccines following pre-authorization clinical trials in non-pregnant people. This study aimed to determine significant health events amongst pregnant females after COVID-19 vaccination, compared with unvaccinated pregnant controls and vaccinated non-pregnant individuals. Methods Study pa...
Article
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Introduction COVID-19 vaccines require enhanced safety monitoring after emergency approval. The Canadian National Vaccine Safety Network monitors the safety of COVID-19 vaccines and provides enhanced monitoring for healthy, auto-immune, immunocompromised, pregnant and breastfeeding populations and allows for the detection of safety signals. Method...
Article
(Abstracted from JAMA 2021;325:2285–2293) Vaccination for seasonal influenza is an important health intervention, even for pregnant women. Influenza vaccination helps to reduce the risk of severe influenza illness for the mother and child.
Preprint
Full-text available
Age is the most important determinant of COVID-19 severity. Infectious disease severity by age is typically J-shaped, with infants and the elderly carrying a high burden of disease. We report on the comparative disease severity between infants and older children in a multicenter retrospective cohort study of children 0 to 17 year old admitted for a...
Preprint
Full-text available
Importance: Children are less likely than adults to have severe outcomes from SARS-CoV-2 infection and the corresponding risk factors are not well established. Objective: To identify risk factors for severe disease in symptomatic children hospitalized for PCR-positive SARS-CoV-2 infection. Design: Cohort study, enrollment from February 1, 2020 unti...
Article
Background: Risk factors for severe outcomes of SARS-CoV-2 infection are not well established in children. We sought to describe pediatric hospital admissions associated with SARS-CoV-2 infection in Canada and identify risk factors for more severe disease. Methods: We conducted a national prospective study using the infrastructure of the Canadia...
Article
Group A Streptococcus (GAS) pharyngitis is a common clinical syndrome in primary care, yet controversy remains regarding the best approach to diagnosis and treatment, including the benefits of antibiotics. Children who are likely to have GAS pharyngitis based on history or physical examination should have a throat swab and, when positive, be treate...
Article
La pharyngite à streptocoque du groupe A est un syndrome clinique courant en première ligne, mais une controverse subsiste quant à la meilleure démarche diagnostique et thérapeutique, y compris les bienfaits des antibiotiques. Les enfants qui, d’après l’anamnèse ou l’examen physique, risquent de souffrir de ce type de pharyngite, doivent se soumett...
Article
Despite ample evidence of the safety and efficacy of the influenza vaccine and the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine during pregnancy, two-thirds of pregnant women do not receive these vaccines. Providers have a significant role in increasing prenatal vaccine uptake. It is important to understand how different sources of v...
Article
Importance Seasonal influenza vaccination in pregnancy can reduce influenza illness among pregnant women and newborns. Evidence is limited on whether seasonal influenza vaccination in pregnancy is associated with adverse childhood health outcomes. Objective To assess the association between maternal influenza vaccination during pregnancy and early...
Article
Background: The World Health Organization recommends immunization with inactivated influenza vac-cine (IIV) and tetanus-diphtheria-acellular pertussis (Tdap) vaccine during pregnancy. Yet, product label-ling information for IIV and Tdap sends a different message. In a previous study, we developed evidence-based statements about vaccination in pregn...
Article
Full-text available
Potential conflicts of interest in vaccine research can lead to negative consequences that undermine public trust and thereby put communities at risk. However, collaborations that may give rise to potential conflicts between interests can also greatly facilitate appropriate, scientifically robust, and timely vaccine development, implementation, and...
Article
Objectives Children with epilepsy are at increased risk of complications from vaccine-preventable infections, yet information on vaccine coverage in these children is scarce. We aimed to compare vaccine coverage among children with epilepsy to children without epilepsy. Study design We conducted a retrospective cohort study including all 2005–2013...
Article
Full-text available
This is a Brighton Collaboration Case Definition of the term “Multisystem Inflammatory Syndrome in Children and Adults (MIS-C/A)” to be utilized in the evaluation of adverse events following immunization. The case definition was developed by topic experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of activ...
Article
Full-text available
Objectives: Our objective was to develop and validate a virtual patient (VP) learning module to educate pediatric residents about antimicrobial stewardship (AMS) principles. A VP module on complicated pneumonia was developed by experts in AMS and pediatric infectious diseases using the online platform DecisionSim™. Decision points were based on AM...
Article
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 nat...
Article
Full-text available
Background The Canadian National Vaccine Safety (CANVAS) network monitors the safety of seasonal influenza vaccines in Canada.AimTo provide enhanced surveillance for seasonal influenza and pandemic influenza vaccines.Methods In 2017/18 and 2018/19 influenza seasons, adults (≥ 15 years of age) and parents of children vaccinated with the seasonal inf...
Article
Background: In children with epilepsy, fever and illness are known triggers for seizure; therefore, clinicians and parents could be concerned that immunization-induced inflammation and fever could also trigger seizures. We sought to estimate the risk of emergency department (ED) visit or hospitalization for epilepsy/seizure and all causes after im...
Article
Full-text available
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 encephalopa...
Article
Full-text available
Background Concern about adverse events following immunization is frequently cited by both those who receive or decline vaccines. Neurological adverse events are especially concerning. Objectives Our aim was to detect associations between seasonal influenza vaccination and the occurrence of severe anesthesia/paresthesia or severe headaches. Metho...
Article
Full-text available
Background: There is no uniform guideline for post-chemotherapy 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 post-chemotherapy DTaP-IPV-Hib and pneumococcal vaccination among previously vacci...
Article
Full-text available
The article provides the definition for Neonatal Seizures for collection of of neonatal and vaccine safety research.
Article
Background: National Regulatory Authorities approve the indications for vaccine use in the product information. Occasionally, National Immunization Technical Advisory Groups (NITAGs) make off-label recommendations for use in different age groups, populations, and dosing schedules from the product information. We sought to determine the rationale,...
Article
Full-text available
Background: Product labelling information describing the use of vaccines in pregnancy continues to contain cautionary language even after clinical and epidemiological evidence of safety becomes available. This language raises safety concerns among healthcare providers who may hesitate to recommend vaccines during pregnancy. Purpose: To develop c...
Article
Chest wall masses in the pediatric population are relatively rare, and the differential diagnosis predominantly includes neoplastic soft tissue or osseous tumours, either benign or malignant in etiology, although local infectious processes represent additional diagnostic possibilities. Among recent immigrants, a more diverse array of less commonly...
Article
Growing evidence suggests receipt of live‐attenuated viral vaccines after solid organ transplant (SOT) has occurred and is safe and needed due to lapses in herd immunity. A 2‐day consortium of experts in infectious diseases, transplantation, vaccinology, and immunology was held with the objective to review evidence and create expert recommendations...
Article
Full-text available
Objective To determine whether any association exists between exposure to 2009 pandemic H1N1 (pH1N1) influenza vaccination during pregnancy and negative health outcomes in early childhood. Design Retrospective cohort study. Setting Population based birth registry linked with health administrative databases in the province of Ontario, Canada. Par...
Article
Full-text available
Objective: To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines ininfants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6 months of life. Methods: Using a standardized searc...
Article
Introduction: 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 appear to be safe but less is known regarding other mAbs, such as anti-integrins and anti-cytokine ag...
Article
Background: While adverse events following immunization (AEFI) are frequent, there are limited data on the safety of reimmunizing patients who had a prior AEFI. Our objective was to estimate the rate and severity of AEFI recurrences. Methods: We analyzed data from the AEFI passive surveillance system in Quebec, Canada that collects information o...
Article
Influenza has been associated with neurological complications. We describe the case of a toddler who presented with symptoms and signs of acute encephalopathy and hydrocephalus. Neuroimaging demonstrated cerebral edema and multifocal diffusion restriction in the thalamus and splenium of the corpus callosum. Influenza A was detected from the nasopha...
Article
Full-text available
Background: Influenza immunization is recommended in pregnancy to prevent severe infections in pregnant women and newborns, yet vaccine uptake remains low. Studies suggest that cautionary language in vaccine product monographs regarding safety and use in pregnancy affects health care providers' perceptions of vaccine safety and how they counsel pre...
Article
Full-text available
Background: In children with epilepsy, fever and infection can trigger seizures. Immunization can also induce inflammation and fever, which could theoretically trigger a seizure. The risk of seizure after immunization in children with pre-existing epilepsy is not known. The study objective was to determine the risk of medically attended seizure af...
Article
Full-text available
We studied the epidemiology of Haemophilus influenzae type b (Hib) infections among children with cancer admitted to Canadian pediatric hospitals. From 1991-2014, 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 immunize...
Article
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Background Smart phone use by medical professionals is ubiquitous. In a recent survey, > 90% of health care providers were interested in locally developed antimicrobial stewardship (AMS) and infectious diseases applications (“apps”). We describe the process by which our antimicrobial stewardship program (ASP) developed an app to provide guidance re...
Article
Full-text available
Background The experience of an adverse event following immunization (AEFI) can increase vaccine hesitancy among patients and health professionals who may be concerned about the risk of a recurrent or more severe event following revaccination. Infectious disease physicians and allergists in the Canadian Special Immunization Clinic (SIC) Network dev...
Article
Full-text available
Context: Reimmunizing patients who had an adverse event following immunization (AEFI) is sometimes a challenge because there are limited data on the risk and severity of AEFI recurrence. Objective: To summarize the literature on the risk of AEFI recurrence. Data sources: PubMed, Embase, and Cochrane library. Study selection: We included arti...
Article
Objectives: During an outbreak of invasive meningococcal B disease on a university campus, we explored the knowledge, attitudes, beliefs, and behaviors of members of the university community in relation to the disease, the vaccine, and the vaccination program. Design: All students, faculty and staff were invited by email to participate in a 71-i...
Article
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 (SIC) Network was established to standardize patient management and assess outcomes after re-immunization. The st...
Article
An outbreak of Neisseria meningitidis serotype B infection occurred at a small residential university; public health announced an organizational vaccination program with the 4-component Meningococcal B (4CMenB) vaccine (Bexsero(TM), Novartis/GlaxoSmithKline Inc.) several days later. Since there were limited published data on reactogenicity of 4CMen...
Article
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Maternal vaccination is an important area of research and requires appropriate and internationally comparable definitions and safety standards. The GAIA group, part of the Brighton Collaboration was created with the mandate of proposing standardised definitions applicable to maternal vaccine research. This study proposes international definitions f...
Article
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Strengthening antenatal care as a platform for maternal immunization is a priority of the World Health Organization (WHO). Systematic surveillance for adverse events following immunization (AEFI) in pregnancy is needed to identify vaccine safety events. We sought to identify active and passive AEFI surveillance systems for pregnant women and infant...
Article
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 d...