Validation of the newly proposed Brighton Collaboration case definition for vaccine-induced immune thrombocytopenia and thrombosis.

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a newly recognized syndrome mediated by anti-platelet factor 4 antibodies induced by Covid-19 adenovirus-vectored vaccines including ChAdOx1 nCoV-19 and Ad26.COV2.S.

Thrombosis with thrombocytopenia syndrome (TTS) and vaccine-induced immune thrombocytopenia and thrombosis (VITT): Brighton Collaboration case definitions and guidelines for data collection, analysis, and presentation of immunisation safety data.

This is a revision of the online November 2021 Brighton thrombosis with thrombocytopenia syndrome (TTS) case definition and a new Brighton Collaboration case definition for vaccine-induced immune thrombocytopenia and thrombosis (VITT). These case definitions are intended for use in clinical trials and post-licensure pharmacovigilance activities to facilitate safety data comparability across multiple settings. They are not intended to guide clinical management.

Anosmia: Brighton Collaboration case definition and guidelines for data collection, analysis, and presentation of immunization safety data.

This is a Brighton Collaboration case definition of anosmia to be used in the evaluation of adverse events following immunization, and for epidemiologic studies for the assessment of background incidence or hypothesis testing. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of SARS-CoV-2 vaccines. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation.

Anaphylaxis: Revision of the Brighton collaboration case definition.

The Brighton Collaboration (BC) has formulated a number of case definitions which have primarily been applied to adverse events of special interest in the context of vaccine safety surveillance. This is a revision of the 2007 BC case definition for anaphylaxis. Recently, the BC definition has been widely used for evaluating reports of suspected anaphylaxis following COVID-19 vaccination.

Thrombosis and thromboembolism: Brighton collaboration case definition and guidelines for data collection, analysis, and presentation of immunization safety data.

This is a Brighton Collaboration case definition of thrombosis and thromboembolism to be used in the evaluation of adverse events following immunization, and for epidemiologic studies for the assessment of background incidence or hypothesis testing. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of SARS-CoV-2 vaccines. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation.

The critical role of background rates of possible adverse events in the assessment of COVID-19 vaccine safety.

Beginning in December of 2019, a novel coronavirus, SARS-CoV-2, emerged in China and is now a global pandemic with extensive morbidity and mortality. With the emergence of this threat, an unprecedented effort to develop vaccines against this virus began. As vaccines are now being introduced globally, we face the prospect of millions of people being vaccinated with multiple types of vaccines many of which use new vaccine platforms.

Vaccine-associated enhanced disease: Case definition and guidelines for data collection, analysis, and presentation of immunization safety data.

This is a Brighton Collaboration Case Definition of the term "Vaccine Associated Enhanced Disease" to be utilized in the evaluation of adverse events following immunization. The Case Definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of vaccines for SARS-CoV-2 vaccines and other emerging pathogens. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation.

Quadrivalent human papillomavirus vaccination in girls and the risk of autoimmune disorders: the Ontario Grade 8 HPV Vaccine Cohort Study.

Background: Despite demonstrated effectiveness in real-world settings, concerns persist regarding the safety of the quadrivalent human papillomavirus (HPV4) vaccine. We sought to assess the risk of autoimmune disorders following HPV4 vaccination among grade 8 girls eligible for Ontario's school-based HPV vaccination program.

Methods: We undertook a population-based retrospective cohort study using Ontario's administrative health and vaccination databases from 2007 to 2013.

Canada's eight-component vaccine safety system: A primer for health care workers.

Concerns about vaccine safety make some parents hesitant about immunization. Health care providers are pivotal in helping parents understand that Canada is a leader in vaccine safety. The present practice point provides an update on the eight components of Canada's vaccine safety system: (1) an evidence-based pre-license review and approval process; (2) strong regulations for manufacturers; (3) independent evidence-based vaccine use recommendations; (4) immunization competency training and standards for health care providers; (5) pharmacovigilance programs to detect and (6) determine causality of adverse events following immunization (AEFIs); (7) a program for vaccine safety and efficacy signal detection; and (8) the Canadian Immunization Research Network's special immunization clinics for children who have experienced serious AEFIs.

Canada's eight-component vaccine safety system: A primer for health care workers.

Concerns about vaccine safety make some parents hesitant about immunization. Health care providers are pivotal in helping parents understand that Canada is a leader in vaccine safety. The present practice point provides an update on the eight components of Canada's vaccine safety system: (1) an evidence-based pre-license review and approval process; (2) strong regulations for manufacturers; (3) independent evidence-based vaccine use recommendations; (4) immunization competency training and standards for health care providers; (5) pharmacovigilance programs to detect and (6) determine causality of adverse events following immunization (AEFIs); (7) a program for vaccine safety and efficacy signal detection; and (8) the Canadian Immunization Research Network's special immunization clinics for children who have experienced serious AEFIs.

Guillain-BarrÉ Syndrome After Immunization in Canadian Children (1996-2012).

Guillain-Barré syndrome (GBS) cases admitted to Canadian pediatric tertiary care centers were ascertained through active surveillance. From 1996 to 2012, 246 cases were identified, and 24 (10%) had onset ≤30 days after immunization. Annual rate of postimmunization GBS was 2.

Immunogenicity, safety, and antibody persistence at 3, 5, and 10 years postvaccination in adolescents randomized to booster immunization with a combined tetanus, diphtheria, 5-component acellular pertussis, and inactivated poliomyelitis vaccine administered with a hepatitis B virus vaccine concurrently or 1 month apart.

An understanding of the antibody persistence elicited by a combined tetanus, diphtheria, 5-component acellular pertussis, and inactivated poliovirus vaccine (Tdap-IPV) after adolescent vaccination is important to optimize booster dosing intervals. Our objectives were to compare the safety and immunogenicity of Tdap-IPV coadministered with hepatitis B vaccine (HepB) and sequential administration and evaluate humoral immunity at 3, 5, and 10 years after Tdap-IPV vaccination in adolescents. This phase II randomized, controlled, and open-label study enrolled 280 11- to 14-year-old adolescents with up to 10 years postvaccination follow-up.

Applicability of the Brighton Collaboration Case Definition for seizure after immunization in active and passive surveillance in Canada.

Background: The Canadian Adverse Event Following Immunization Surveillance System (CAEFISS) receives reports via active syndromic surveillance for selected serious AEFI from the Canadian Immunization Monitoring Program Active (IMPACT) and via targeted passive surveillance from Federal/Provincial/Territorial health jurisdictions. Post-immunization seizure is a target of active and passive surveillance. Since 2009, the revised national AEFI reporting forms enable capture of terms specific to several Brighton Collaboration Case Definitions (BCCD) including generalized seizure and fever.

Sustained elevation of systemic oxidative stress and inflammation in exacerbation and remission of asthma.

Oxidative stress has been implicated in the pathogenesis of asthma. We aimed at investigating the biomarkers of oxidative stress, inflammation, and tissue damage in patients with asthma in acute exacerbation and remission. We recruited 18 asthmatics admitted to hospital with acute exacerbation and 18 healthy nonsmoking controls matched for age.

Assessment of causality of individual adverse events following immunization (AEFI): a WHO tool for global use.

Serious illnesses or even deaths may rarely occur after childhood vaccinations. Public health programs are faced with great challenges to establish if the events presenting after the administration of a vaccine are due to other conditions, and hence a coincidental presentation, rather than caused by the administered vaccines. Given its priority, the Global Advisory Committee for Vaccine Safety (GACVS) commissioned a group of experts to review the previously published World Health Organization (WHO) Adverse Event Following Immunization (AEFI) causality assessment methodology and aide-memoire, and to develop a standardized and user friendly tool to assist health care personnel in the processing and interpretation of data on individual events, and to assess the causality after AEFIs.

On-time vaccination coverage in premature infants in Ontario, 2002-2009.

Objective: Premature children are at increased risk of complications from vaccine-preventable diseases and should be vaccinated with the routinely recommended childhood vaccines at the same chronological age as full-term infants with the exception of the hepatitis B vaccine for infants of HBsAg-positive mothers. We sought to compare on-time vaccination levels in premature children for recommended vaccinations to levels in children born at term.

Methods: Using linked health administrative databases, we compared the proportion of term (37+ wks), near term (33-36 wks), very premature (28-32 wks) and extremely premature (≤27 wks) children who received at least one vaccination during the 2-, 4- and 6-month vaccination visits within the recommended time period in the province of Ontario.

The effect of funded varicella immunization programs on varicella-related hospitalizations in IMPACT centers, Canada, 2000-2008.

Background: The 12 Immunization Monitoring Program, Active (IMPACT) centers that represent 90% of pediatric tertiary care beds in Canada conducted active surveillance for varicella-related hospitalizations and complications from 1999 onward, after varicella vaccine was authorized. Publicly funded routine immunization programs at 12 or 15 months of age were introduced by 5 provinces and territories (prov/terr) in 2000 to 2002 (earlier programs, EP) and by 8 prov/terr in 2004 to 2007 (later programs, LP).

Objective: To determine whether the number of varicella-related hospitalized cases had declined by 2008 at 12 IMPACT centers after the sequential introduction of publicly funded varicella immunization programs in Canada.

Influenza vaccine effectiveness in the elderly based on administrative databases: change in immunization habit as a marker for bias.

Background: Administrative databases provide efficient methods to estimate influenza vaccine effectiveness (IVE) against severe outcomes in the elderly but are prone to intractable bias. This study returns to one of the linked population databases by which IVE against hospitalization and death in the elderly was first assessed. We explore IVE across six more recent influenza seasons, including periods before, during, and after peak activity to identify potential markers for bias.

The responses of Aboriginal Canadians to adjuvanted pandemic (H1N1) 2009 influenza vaccine.

Background: Because many Aboriginal Canadians had severe cases of pandemic (H1N1) 2009 influenza, they were given priority access to vaccine. However, it was not known if the single recommended dose would adequately protect people at high risk, prompting our study to assess responses to the vaccine among Aboriginal Canadians.

Methods: We enrolled First Nations and Métis adults aged 20-59 years in our prospective cohort study.

Case report: probable transmission of vaccine strain of yellow fever virus to an infant via breast milk.

The 17D yellow fever vaccine is a live-virus vaccine that has been in use since the 1940s. The incidence of encephalitis after yellow fever vaccination among young infants is much higher than among children older than nine months of age. Until recently, avoidance of vaccination by breastfeeding women who have received yellow fever vaccine had been based on theoretical grounds only.

Evaluation of adjuvanted pandemic H1N1(2009) influenza vaccine after one and two doses in young children.

Background: When Canada chose an adjuvanted influenza A H1N1(2009) vaccine for pandemic control, dosing requirements and safety in children were unknown. This study compared responses after 1 and 2 doses in young children.

Methods: Five Canadian centers evaluated ASO3-adjuvanted H1N1(2009) vaccine (Arepanrix, GSK Laval, Quebec) in children aged 6 to 35 months, given 2 doses (0.

Can the Brighton Collaboration case definitions be used to improve the quality of Adverse Event Following Immunization (AEFI) reporting? Anaphylaxis as a case study.

The Brighton Collaboration (BC) was established in 2000 with the aim of developing globally accepted standardized case definitions for adverse events following immunizations (AEFI) as well as guidelines for the collection, analysis and presentation of surveillance data. Some of the BC case definitions are complex and this may limit their application for use in post-marketing vaccine surveillance. Barriers to the application of the BC case definitions include an incomplete description of an adverse event and inconsistencies in reporter use of adverse event terms.

Postvaccination thrombocytopenia in Canada.

Active surveillance data from 12 Canadian tertiary-care hospitals on children hospitalized with postvaccination thrombocytopenia were analyzed. Since 1992, there have been 107 cases reported; while 96% of the children were symptomatic, only 2 had severe bleeding. With treatment, 28 children (26%) had normal platelet counts on discharge from hospital and 93% had documented recovery within 3 months.