Kawasaki disease and immunisation: A systematic review

Kawasaki disease and the environment: an enigmatic interplay

Kawasaki disease (KD) is a common systemic vasculitis of childhood. Although it has been almost 6 decades since Dr. Tomisaku Kawasaki reported the first case series of KD, the underlying cause remains a mystery. KD is a self-limiting disease. However, a dreaded complication is development of coronary artery abnormalities (CAAs). KD is the most common cause of acquired heart disease in children in the developed world and is being increasingly reported from developing countries too. Over the years, significant observations have been made about epidemiology of KD. It usually affects children below 5, has male preponderance and has significantly higher incidence in North East Asian countries. While several hypotheses have been proffered for etiology of KD, none have been conclusive. These include associations of KD epidemics in Japan and the United Stated with changes in tropospheric wind patterns suggesting wind-borne agents, global studies showing peaks of incidence related to season, and increased rates in populations with a higher socioeconomic profile related to hygiene hypothesis and vaccination. Furthermore, the self-limiting, febrile nature of KD suggests an infectious etiology, more so with sudden decline noted in cases in Japan with onset of COVID-19 mitigation measures. Finally, single nucleotide polymorphisms have been identified as possible risk alleles in patients with KD and their significance in the pathogenesis of this disease are also being defined. The purpose of this review is to elucidate the puzzling associations of KD with different environmental factors. Looking at patterns associated with KD may help us better predict and understand this disease.

Occurrence of Kawasaki disease and neoplasms in temporal proximity-single-center experience and systematic review of literature

Various factors (e.g., infections) have been postulated to trigger Kawasaki disease (KD) in genetically predisposed individuals. Whether neoplasms can trigger KD is largely unknown due to paucity of data. Herein, we provide a detailed account of KD occurring in temporal proximity (within 6 months) to neoplasms ('neoplasm-KD'). Patients with 'neoplasm-KD' diagnosed/treated at our center from January 1994 to May 2021 were included. Additionally, we performed a systematic literature review (as per PRISMA 2020 guidelines) utilizing PubMed, Web of Science and Scopus databases to retrieve details of all patients with 'neoplasm-KD' reported till June 2021. Patients with multisystem inflammatory syndrome in children were excluded. As all reports pertained to case description(s), risk of bias assessment was not performed. The details of patients with 'neoplasm-KD' were analyzed using SPSS software. Primary and secondary outcomes were occurrence of coronary artery abnormalities (CAAs) and clinical characteristics of 'neoplasm-KD', respectively. A total of 25 patients (data from 18 reports) were included in the 'neoplasm-KD' dataset. The most frequently diagnosed neoplasm was acute lymphoblastic leukemia followed by neuroblastoma and acute myeloblastic leukemia. Overall, CAAs were noted in 48% of patients. Interval between diagnoses of KD and neoplasm was shorter in patients with CAAs as compared to patients with normal coronary arteries (p-value = 0.03). Besides providing a comprehensive description of 'neoplasm-KD', this study raises a possibility that neoplasms might trigger KD. Also, 'neoplasm-KD' may be associated with a higher risk of development of CAAs. However, the small size of 'neoplasm-KD' dataset precludes definitive conclusions regarding this association. Funding: nil. Registration: PROSPERO (CRD42021270458).

Safety of varicella vaccination strategies: An overview of reviews

The safety of new vaccines under development as well as existing vaccines is a key priority for national and international public health agencies. A number of countries have implemented universal childhood varicella vaccination programmes over the past 30 years. However, strategies differ in terms of the number of doses, type of vaccine(s) recommended, age at vaccination and interval between doses for a two-dose schedule. An overview of reviews was undertaken to assess the existing systematic review evidence of the safety of varicella vaccination strategies. The review was restricted to immunocompetent children aged 9 months to 6 years inclusive. A comprehensive search of databases, registries and grey literature was conducted up to 2 February 2022. Two reviewers independently screened, extracted data and assessed the methodological quality of included reviews. Overlap of included reviews was also assessed. A total of 17 reviews, incorporating both the monovalent varicella only and quadrivalent measles-mumps-rubella-varicella (MMRV) vaccines were included in the overview; six assessed the safety of one-dose strategies, four assessed the safety of two-dose strategies and 14 reviews did not specify the dosing strategy. The evidence suggests that mild local and systemic reactions are relatively common with varicella vaccination. Febrile seizures are also possible adverse effects of both the monovalent and quadrivalent MMRV vaccine, but serious adverse reactions are rare. While most reviews contained methodological flaws, and analysis by vaccine type and dosing strategy was restricted due to lack of detail in reporting of the reviews, there was clear and consistent evidence from a substantial evidence base, comprising 34 randomised controlled trials and 62 other primary studies/reviews, that varicella vaccination is safe.

Kawasaki Disease Following the 13-valent Pneumococcal Conjugate Vaccine and Rotavirus Vaccines

BACKGROUND

Temporal associations between Kawasaki disease (KD) and childhood vaccines have been reported. Limited data on KD following 13-valent pneumococcal conjugate (PCV13) and rotavirus vaccines are available.

METHODS

We conducted a self-controlled risk interval study using Vaccine Safety Datalink electronic health record data to investigate the risk of KD following PCV13 and rotavirus vaccines in children <2 years of age who were born from 2006 to 2017. All hospitalized KD cases identified by International Classification of Diseases diagnosis codes that fell within predefined risk (days 1-28 postvaccination) and control (days 29-56 for doses 1 and 2, and days 43-70 for doses 3 and 4) intervals were confirmed by manual chart review.

RESULTS

During the study period, 655 cases of KD were identified by International Classification of Diseases codes. Of these, 97 chart-confirmed cases were within risk or control intervals. In analyses, the age-adjusted relative risk for KD following any dose of PCV13 was 0.75 (95% confidence interval, 0.47-1.21). Similarly, the age-adjusted relative risk for KD following any dose of rotavirus vaccine was 0.66 (95% CI, 0.40-1.09). Overall, there was no evidence of an elevated risk of KD following PCV13 or rotavirus vaccines by dose. In addition, no statistically significant temporal clustering of KD cases was identified during days 1 to 70 postvaccination.

CONCLUSIONS

PCV13 and rotavirus vaccination were not associated with an increased risk of KD in children <2 years of age. Our findings provide additional evidence for the overall safety of PCV13 and rotavirus vaccines.

Kawasaki disease following immunization reported to the Canadian Immunization Monitoring Program ACTive (IMPACT) from 2013 to 2018

Kawasaki disease (KD) is an acute systemic vasculitis primarily affecting children younger than 5 y of age that has been reported as an adverse event following immunization (AEFI). The Canadian Immunization Monitoring Program ACTive (IMPACT) conducts active surveillance for KD following immunization across Canada. We characterized KD cases reported to IMPACT between 2013 and 2018. Cases admitted to an IMPACT hospital with a physician diagnosis of complete or incomplete KD with onset 0–42 d following vaccination were reviewed. Cases meeting the Brighton Collaboration case definition (BCCD) levels of diagnostic certainty levels 1 a/b, 2a/b or 3a-e were defined as KD cases. Demographic and vaccination characteristics were compared between KD cases and non-cases. Of 84 cases reviewed, 58 met the BCCD: 47 (81%) cases met level 1a (Complete KD), 8 (14%) met level 1b (Incomplete KD), 2 (3%) met level 2a, and 1 (2%) met level 2c (Probable KD). Median age at admission was 13 months (interquartile range 7–26 months). A median of 9.5 cases were reported per year (range 4–14). Thirty-one (53%) KD cases were temporally associated with diphtheria-tetanus acellular pertussis containing vaccinations, followed by 21 (36%) cases with pneumococcal conjugate vaccines. Symptom onset was 0–14 d after vaccination in 32 (55%) cases. Echocardiogram results were available for 43 (74%) cases with 22 reported as abnormal. Age, sex, interval to symptom onset, and vaccines received were similar between KD cases and non-cases. No safety signals were detected in these data.

Case of adult-onset Kawasaki disease and multisystem inflammatory syndrome following SARS-CoV-2 vaccination

Kawasaki disease (KD) and multisystem inflammatory syndrome (MIS) are rare conditions that occur predominately in children. Recent reports document KD and MIS in adult patients following infection with SARS-CoV-2. Rarely, MIS is observed following vaccination against SARS-CoV-2, mostly in patients with prior SARS-CoV-2 infection. We report a case of KD in a man after a second SARS-CoV-2 vaccine dose, in absence of concurrent or prior SARS-CoV-2 infection. This patient also met criteria for probable MIS associated with vaccination. He tested negative for SARS-CoV-2 RNA via reverse transcriptase PCR, negative for SARS-CoV-2 nucleocapsid antibodies and demonstrated high levels SARS-CoV-2 spike protein antibodies, commonly used to assess vaccine response. Symptom improvement followed treatment with intravenous immunoglobulin, including desquamation of the hands and feet. As widespread vaccination against SARS-CoV-2 continues, increased vigilance and prompt intervention is necessary to limit the effects of postvaccination inflammatory syndromes.

Multisystem Inflammatory Syndrome in Adult Following COVID-19 Vaccination (MIS-AV)

The last 2 years have been dominated by coronavirus disease-2019 (COVID-19), its various presentations, complications, and their management. The first COVID-19 vaccine, produced by Pfizer-BioNTech, was granted regulatory approval on December 2, 2020, by the UK medicines regulator medicines and healthcare products regulatory agency (MHRA). It was evaluated for emergency use authorization (EUA) status by the US Food and Drug Administration (FDA) and in several other countries. Following millions of doses, during the early months of 2021, reports of side effects of the vaccines began to emerge. In this case report, we discuss the case of a 22-year-old female patient who presented with fever and confusion, with later progression to multiple organ failure, following administration of Pfizer-BioNTech vaccine. She was successfully treated with intravenous (IV) immunoglobulin (Ig) and high-dose IV corticosteroids. This case report is unique as lymph node biopsy was carried out—this showed marked suppurative inflammation with vasculitic changes, thus supporting the diagnosis.

Effect of breastfeeding for 6 months on disease outcomes in patients with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is a systematic vasculitis that occurs predominantly in young children, and is the leading cause of acquired heart disease in children younger than five-years-old in developed countries. Although the etiology of KD is unknown, it is believed to be an inflammatory disease resulting from abnormal immune responses to possible environmental or infectious stimuli in genetically predisposed individuals. Breast milk contains numerous anti-inflammatory factors which may protect against allergic and autoimmune diseases. In this study we tried to examine the effect of breastfeeding for 6 months or more on disease outcomes in patients with Kawasaki disease.

METHODS

A retrospective cohort study of 249 KD patients admitted from 1999- 2013 who were older than 6 months at time of diagnosis and had data regarding breastfeeding in the first 6 months of life. Demographic, clinical and laboratory data was collected by chart review. Continuous data was compared using Student's t-test and categorical variables were compared using Chi-square. Stepwise multivariate regression of all demographic factors was performed.

RESULTS

Breastfeeding for 6 months or more was associated with a shorter total duration of fever (5.980± 1.405 Vs. 6.910 ± 2.573 days, p = 0.001) and a lower risk of developing persistent coronary artery lesions (CALs) (7.8% Vs. 20.2%, p-value = 0.039) on univariate analysis. Multivariate regression of all factors associated with CALs including breastfeeding for 6 months found that only the presence of CALs at baseline (β-coefficient = 0.065, p < 0.001) and white blood count (β-coefficient = 0.065, p = 0.018) remained significant after regression analysis.

CONCLUSIONS

Breastfeeding for 6 months or more was associated with a shorter duration of fever and a lower risk of persistent CAL formation in patients with KD on univariate analysis, although this effect may be modest when other factors such as the presence of CALs at baseline and white blood cell count are also taken into consideration.

Multisystem Inflammatory Syndrome in an Adult after COVID-19 Vaccination: a Case Report and Literature Review

As the number of people vaccinated increases, people who complain of adverse reactions continue to occur. We experienced a case characterized by low blood pressure, persistent fever, edema due to increased systemic vascular permeability, and systemic inflammation confirmed by image and laboratory examinations after ChAdOx1 coronavirus disease 2019 (COVID-19) vaccination. The diagnostic criteria for multisystem inflammatory syndrome (MIS) in adults are known as fever of 3 days or more in adults, 2 or more mucocutaneous/gastrointestinal/neurologic symptoms, elevation of inflammatory markers, and clinical/imaging diagnosis of heart failure. A 67-year-old man who was medicated for hypertension and diabetes was admitted complaining of fever, maculopapular rash, diarrhea, headache, chills, and dizziness 6 days after the first vaccination of ChAdOx1 nCoV-19 in Korea. The COVID-19 test was negative but with low blood pressure, leukocytosis, skin rash, pulmonary edema, and increased inflammation markers. His lab findings and clinical course were consistent with those of MIS after COVID-19 vaccination. He was medicated with methylprednisolone 1 mg/kg and diuretics and recovered rapidly. He was discharged after 2 weeks and confirmed cure at outpatient clinic. We report an MIS case after COVID-19 vaccination in Korea.

Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination for Paediatric Patients With Inflammatory Bowel Diseases

In this communication, the members of the Porto group (the European Society for Paediatric Gastroenterology, Hepatology and Nutrition [ESPGHAN], inflammatory bowel diseases [IBD] working group) provide the current available evidence regarding vaccination of children and young adolescents with IBD against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our intent is to help provide meaningful answers to the concerns that parents and adolescents may have.

Safety, Immunogenicity, and Efficacy of COVID-19 Vaccines in Children and Adolescents: A Systematic Review

AIM

To identify the safety, immunogenicity, and protective efficacy of COVID-19 vaccines in children and adolescents.

METHODS

We conducted a systematic review of published studies and ongoing clinical studies related to the safety, immunogenicity, and efficacy of COVID-19 vaccine in children or adolescents (aged < 18 years). Databases including PubMed, Web of Science, WHO COVID-19 database, and China National Knowledge Infrastructure (CNKI) were searched on 23 July 2021. International Clinical Trials Registry Platform (ICTRP) was also searched to identify ongoing studies.

RESULTS

Eight published studies with a total of 2852 children and adolescents and 28 ongoing clinical studies were included. Of the eight published studies, two were RCTs, two case series, and four case reports. The investigated COVID-19 vaccines had good safety profiles in children and adolescents. Injection site pain, fatigue, headache, and chest pain were the most common adverse events. A limited number of cases of myocarditis and pericarditis were reported. The RCTs showed that the immune response to BNT162b2 in adolescents aged 12-15 years was non-inferior to that in young people aged 16-25 years, while with 3 μg CoronaVac injection the immune response was stronger than with 1.5 μg. The efficacy of BNT162b2 was 100% (95% CI: 75.3 to 100), based on one RCT. Of the 28 ongoing clinical studies, twenty-three were interventional studies. The interventional studies were being conducted in fifteen countries, among them, China (10, 43.5%) and United States(9, 39.1%) had the highest number of ongoing trials. BNT162b2 was the most commonly studied vaccine in the ongoing trials.

CONCLUSION

Two COVID-19 vaccines have potential protective effects in children and adolescents, but awareness is needed to monitor possible adverse effects after injection. Clinical studies of the COVID-19 vaccination in children and adolescents with longer follow-up time, larger sample size, and a greater variety of vaccines are still urgently needed.

Kawasaki Disease and Vaccination: Prospective Case-Control and Case-Crossover Studies among Infants in Japan

The causal effects of vaccines on Kawasaki disease (KD) remain elusive. We aimed to examine the association between vaccines administered during infancy and the development of KD in Japan. We conducted a multicenter prospective case-control study using questionnaires and compared the vaccination status of infants (age: 6 weeks to 9 months) who developed KD (KD group; n = 102) and those who did not develop KD (non-KD group; n = 139). Next, we performed a case-crossover study of 98 cases in the KD group and compared the status of vaccinations between the case and control periods. We also compared the incidence of KD in children for each 5-year period before and after the addition of new vaccines (2012–2013) using data from the Nationwide Survey of KD. In the case-control study, the vaccination status of the KD and control groups did not differ to a statistically significant extent. Multivariable analysis of the vaccination status and patient backgrounds showed no significant association between vaccination and KD development. In the case-crossover study, the status of vaccinations during the case and control periods did not differ to a statistically significant extent. In the analysis of data from the Nationwide Survey of KD, the incidence of KD in children of ages subject to frequent vaccination showed no significant increases in the latter five years, 2014–2018. Based on these prospective analyses, we confirmed that vaccination in early infancy did not affect the risk of KD.

Multisystem inflammatory syndrome in an adult following the SARS-CoV-2 vaccine (MIS-V)

SARS-CoV-2 vaccine roll-out has been successful in the UK and other parts of the world; however, there are increasing concerns about adverse events. A 44-year-old woman presented to a UK hospital with left upper arm pain at the vaccine site a couple of days after receiving the Pfizer-BioNTech mRNA vaccine, which progressed to fever, diarrhoea and abdominal pain over the next few days. She had an erythematous rash on the chest with subcutaneous oedema. Her C reactive protein was 539 mg/L, white cell count of 17×10⁹/L (1.8–7.5), troponin-T of 1013 ng/L and creatine kinase of 572 u/L. She developed an unprovoked pulmonary embolism with acute kidney injury. After administration of intravenous methylprednisolone, the muscle oedema, skin rashes and acute kidney injury resolved. Although multisystem inflammatory syndrome (MIS) is described in children (MIS-C) and adults (MIS-A) following SARS-CoV-2 infection, we highlight the first reported MIS-V case after the SARS-CoV-2 vaccine.

Observation on the clinical effect of high-dose Intravenous Immunoglobulin combined with low-dose prednisone acetate in the treatment of patients with Kawasaki Disease

Objective:

To evaluate the clinical effect of high-dose intravenous immunoglobulin (HDIVIG) single dose and pulse therapy combined with small-dose prednisone acetate in the treatment of patients with Kawasaki disease (KD).

Methods:

Eighty patients with KD from Baoding Children’s Hospital, China, were randomly divided into two groups: the experimental group and the control group, each with 40 cases. Patients in the experimental group were treated with HDIVIG single dose, pulse therapy combined with low-dose prednisone acetate, while patients in the control group were treated with conventional-dose immunoglobulin. Patients in both groups were treated with aspirin orally, and given symptomatic treatment including anti-inflammatory, nutritional support, correction of water and electrolyte disturbance and acid-base balance. Peripheral venous blood samples were drawn from all patients at the time of admission, Day-1, Day-7 and Day-14 after treatment, and in the basic state of getting up in the morning, and then the levels of tumor necrosis factor (TNF-a), C-reactive protein (CRP), interleukin-6 (IL-6) and other inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). The time of body temperature falling to normal, lymph node swelling recovery, hands and feet swelling, mucosal hyperemia regression after treatment in the two groups was recorded, and the treatment effect of the two groups was comprehensively evaluated.

Results:

After treatment, the levels of inflammatory factors such as TNF-a, CRP, IL-6 in the experimental group were significantly lower than those in the control group, with a statistically significant difference (P<0.05). In addition, the time of body temperature falling to normal, lymph node swelling recovery, hands and feet swelling, and mucosal hyperemia regression in the experimental group was significantly shorter than that in the control group (p=0.00). The effective rate of the experimental group was 95% and that of the control group was 80%, with a statistically significant difference (p=0.04).

Conclusion:

HDIVIG single dose, pulse therapy combined with small-dose prednisone acetate has a favourable therapeutic effect in the treatment of patients with KD, by which the inflammatory factors can be significantly improved, clinical symptoms and weight can be quickly ameliorated, and therapeutic effect can be enhanced.

Multisystem inflammatory syndrome in children and adults (MIS-C/A): Case definition & guidelines for data collection, analysis, and presentation of immunization safety data

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 active development of vaccines for SARS-CoV-2. The format of the Brighton Collaboration was followed, including an exhaustive review of the literature, to develop a consensus definition and defined levels of certainty. The document underwent peer review by the Brighton Collaboration Network and by selected expert external reviewers prior to submission. The comments of the reviewers were taken into consideration and edits incorporated into this final manuscript.

Assessing safety of Ontario’s publicly funded MMR and MMRV immunization programs, 2012 to 2016

Background

The combined measles, mumps, rubella (MMR) and measles, mumps, rubella, and varicella (MMRV) vaccines are part of Ontario’s routine immunization schedule.

Objective

To assess adverse events following immunization (AEFIs) reported in Ontario following administration of MMR and MMRV vaccines between 2012 and 2016.

Methods

Reports of AEFIs were extracted from the provincial surveillance database on May 9, 2017. Events were grouped by provincial surveillance definitions. Reporting rates were calculated using provincial population estimates or net doses distributed as the denominator. A serious AEFI is defined as an AEFI that resulted in an in-patient hospitalization or death.

Results

Overall, 289 AEFIs were reported following administration of MMR (n=246) or MMRV (n=43) vaccines, for annualized reporting rates of 16.6 and 8.8 reports per 100,000 distributed doses, respectively. The highest age-specific reporting rate was in children aged 1 to 3 years for MMR (7.7 per 100,000 population) and children aged 4 to 9 years for MMRV (0.8 per 100,000 population). Systemic reactions were the most frequently reported event category, while rash was the most frequently reported event for both vaccines. There were 22 serious AEFIs, 19 following MMR and 3 following MMRV (1.3 and 0.6 per 100,000 doses distributed, respectively).

Conclusions

Our assessment found a low reporting rate of adverse events following MMR and MMRV vaccines in Ontario. No safety concerns were identified. Our findings are consistent with the safety profiles of these vaccines. Continued monitoring of vaccine safety is necessary to maintain timely detection of unusual postvaccine events and public confidence in vaccine safety.

The risk of Kawasaki disease after pneumococcal conjugate & meningococcal B vaccine in England: A self-controlled case-series analysis

Kawasaki disease (KD) is an uncommon condition occasionally reported after childhood vaccination. Admissions with a KD-compatible diagnosis identified from a national database in England were linked to immunisation records to investigate the risk after pneumococcal conjugate (PCV) or meningococcal B (MenB) vaccines. Both are given at 2/4/12 months of age but were introduced sequentially, allowing their effects to be separately assessed. A total of 553 linked admissions in 512 individuals were validated as KD. The relative incidence (RI) within 28 days of PCV doses 1 or 2 measured by the self-controlled case-series method was 0.62 (95% confidence interval (CI) 0.38-1.00) with a significantly decreased risk after dose 3 (RI 0.30 (95% CI 0.11-0.77)). For MenB vaccine, the RI after doses 1 or 2 was 1.03 (95% CI 0.51-2.05) and 0.64 (95% CI 0.08-5.26) after dose 3. This study shows no evidence of an increased risk of KD after either vaccine.

Kawasaki Disease following administration of 13-valent pneumococcal conjugate vaccine in young children

Kawasaki disease (KD) is a systemic vasculitis mainly affecting young children and the leading cause of acquired heart disease in developed countries. We performed a self-controlled case series analysis to investigate the association between PCV13 and KD. All hospitalized KD cases <2 y old from our hospital in Singapore from 2010 to 2014 were included. Complete KD cases were classified based on the definitions of the American Heart Association. During the study period, 288 KD cases were identified. A total of 21 KD cases (12 were classified as Complete KD) had date of onset within the risk interval of day 1 to day 28 post PCV13. The age-adjusted Relative Incidence (RI) for KD following PCV13 dose 1, dose 2 and dose 3 were 1.40 (95%CI, 0.72 to 2.71), 1.23 (95% CI, 0.62 to 2.44) and 0.34 (95% CI, 0.08 to 1.40) respectively. There were seven Complete KD cases with onset during the risk interval after dose 1 of PCV13 (age-adjusted RI 2.59, 95%confidence interval (CI), 1.16 to 5.81). We did not detect a significant increased risk for overall KD among PCV13 recipients. However, a significant association between PCV13 and Complete KD was noted following receipt of the first dose of PCV13.

Extra-pulmonary diseases related to Mycoplasma pneumoniae in children: recent insights into the pathogenesis

PURPOSE OF REVIEW

Providing an overview on Mycoplasma pneumoniae-related extra-pulmonary diseases (MpEPDs) in children, who represent the preferred target population by those complications, and discussing the main pathogenic mechanisms implicated or potentially involved.

RECENT FINDINGS

Recent evidences supported the fact that M. pneumoniae is more than an extra-cellular pathogen colonizing epithelial cells of the respiratory tract. It is able to penetrate the cell membrane of host cells and to invade the respiratory mucosa, leading to pronounced inflammatory responses and also spreading outside the respiratory system, to some extent. Thus, direct and indirect (immune-mediated) mechanisms have been described in M. pneumoniae infections, but the latter ones have been mainly implicated in MpEPDs, as reviewed here. Recently, interesting insights have been provided, especially as concern neurologic complications, and new potential mechanisms of disease have been emerging for autoimmunity.

SUMMARY

The awareness of the occurrence of MpEPDs, showing very variable clinical expressions, could promote a correct diagnosis and an appropriate treatment. The knowledge of disease mechanisms in MpEPDs is largely incomplete, but recent advances from clinical studies and murine models might promote and direct future research.

Post-marketing surveillance to assess the safety and tolerability of a combined diphtheria, tetanus, acellular pertussis and inactivated poliovirus vaccine (DTaP-IPV) in Korean children

Infanrix-IPV (GSK, Belgium) is a diphtheria, tetanus, acellular pertussis, and inactivated poliovirus combination vaccine (DTaP-IPV) licensed in many countries including Korea. In accordance with Korean regulations, we conducted a post-marketing surveillance (PMS) to evaluate the safety of DTaP-IPV administered to Korean children in routine immunization schedules. Children aged <7 years receiving at least one dose of DTaP-IPV either as part of a primary (3-dose) vaccination series or as a subsequent booster were enrolled. Adverse events (AEs), adverse drug reactions (ADRs) and serious AEs (SAEs) were recorded after each dose during the 30-day post-vaccination follow-up period. Among a total of 639 children, 289 subjects (45.2%) experienced AEs, mostly (79.2%) assessed as being unlikely to be related to the vaccination. ADRs were reported in 13.0% of subjects. Fever was the most commonly reported expected AE (11.9% of subjects) and also the most commonly reported expected ADR (8.5% of subjects). No obvious association between AE incidence and vaccine dose sequence was apparent. An unexpected AE was seen in 32.9% of children, and unexpected ADRs were far less common (1.9%). Thirty-four SAEs were recorded in 26 subjects (4.1%), in two of whom a causal association with the vaccine could not be excluded, although both resolved quickly. Data from this PMS indicate that DTaP-IPV has an acceptable safety profile when given to Korean children in accordance with local prescribing recommendations in routine childhood immunization. ClinicalTrials.gov identifier: NCT01568060

Demonstration of background rates of three conditions of interest for vaccine safety surveillance

INTRODUCTION

Adverse events following immunization (AEFIs) are unwanted or unexpected health outcomes following vaccination, which may or may not be causally-linked to vaccines. AEFI reporting is important to post-marketing vaccine safety surveillance and has the potential to identify new or rare AEFIs, show increases in known AEFIs, and help to maintain public confidence in vaccine programs. Knowledge of the expected incidence (i.e. background rate) of a possible AEFI is essential to the investigation of vaccine safety signals. We selected three rarely reported AEFIs representing the spectrum of causal association with vaccines, from proven (immune thrombocytopenia [ITP]) to questioned (Kawasaki disease [KD]) to unsubstantiated (multiple sclerosis [MS]) and determined their background rates.

METHODS

We extracted data on hospitalizations (CIHI Discharge Abstract Database) for ITP, KD, and MS among Ontario children for the period 2005 to 2014 from IntelliHEALTH. As ITP can be managed without hospitalization, we also extracted emergency department (ED) visits from the CIHI National Ambulatory Care Reporting System. For all conditions, we only counted the first visit and if the same child had both an ED visit and a hospitalization for ITP, only the hospitalization was included. We calculated rates by year, age group and sex using population estimates from 2005-2014, focusing on age groups within the Ontario immunization schedule around vaccine(s) of interest.

RESULTS

Per 100,000 population, annual age-specific incidence of ITP in children age 1 to 7 years ranged from 8.9 to 12.2 and annual incidence of KD in children less than 5 years ranged from 19.1 to 32.1. Average annualized incidence of adolescent (11-17 years) MS across the study period was 0.8 per 100,000.

DISCUSSION

Despite limitations, including lack of clinical validation, this study provides an example of how health administrative data can be used to determine background rates which may assist with interpretation of passive vaccine safety surveillance.