Associations between the spatiotemporal distribution of Kawasaki disease and environmental factors: evidence supporting a multifactorial etiologic model

Resurgence of Kawasaki Disease Following Relaxation of Coronavirus Disease 2019 Pandemic Restrictions in Japan

OBJECTIVES

To compare the number and incidence of Kawasaki disease (KD) patients in years 2 through 4 of the coronavirus disease 2019 (COVID-19) pandemic, and determine the impact of 3 years of implementation infection control measures and their subsequent relaxation on the epidemiology of KD in Japan.

STUDY DESIGN

We conducted a population-based, cohort study including consecutive KD patients in Kobe City between 2021 and 2023. We compared the incidence of KD cases, in relation to timing of infection control measures, as well as infectious disease cases based on a regional surveillance system. Data from a previous 2016 through 2020 study were used for comparison.

RESULTS

A total of 566 children with KD were identified during the study period. During the infection control period in 2021 to 2022, the incidence of KD remained low compared with the pre-pandemic level (281.3 and 327.5/100,000 children aged 0-4 years in 2021to 2022 and 2016 through 2019, respectively), but a recovery trend began in the 0-1-year age group. During the relaxation period in 2023, the incidence of KD increased across a wide age range, reaching the highest recorded in Japan (426.7/100,000 children aged 0-4 years), and the median age of onset increased to age 30 months. The resurgence of KD coincided with the patterns for multiple infectious diseases in 2023. The seasonality of KD observed before the pandemic was altered.

CONCLUSIONS

KD resurged in 2023 after relaxation of the prolonged COVID-19 pandemic restrictions in Japan. This phenomenon coincided with the rise of multiple infectious diseases, and supports the pathogenesis of KD being triggered by infectious agents.

The Future of Kawasaki Disease Diagnosis: Liquid Biopsy May Hold the Key

Kawasaki disease (KD) is a febrile illness characterised by systemic inflammation of small- and medium-sized blood vessels, which commonly occurs in young children. Although self-limiting, there is a risk of developing coronary artery lesions as the disease progresses, with delay in diagnosis and treatment. Unfortunately, the diagnosis of KD continues to remain a clinical dilemma. Thus, this article not only summarises the key research gaps associated with KD, but also evaluates the possibility of using circulating endothelial injury biomarkers, such as circulating endothelial cells, endothelial microparticles and vascular endothelial cell-free DNA, as diagnostic and prognostic tools for KD: a "liquid biopsy" approach. The challenges of translating liquid biopsies to use in KD and the opportunities for improvement in its diagnosis and management that such translation may provide are discussed. The use of endothelial damage markers, which are easily obtained via blood collection, as diagnostic tools is promising, and we hope this will be translated to clinical applications in the near future.

Kawasaki Disease in the Time of COVID-19 and MIS-C: The International Kawasaki Disease Registry

BACKGROUND

Patients with multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD) have overlapping clinical features. We compared demographics, clinical presentation, management, and outcomes of patients according to evidence of previous SARS-CoV-2 infection.

METHODS

The International Kawasaki Disease Registry (IKDR) enrolled KD and MIS-C patients from sites in North, Central, and South America, Europe, Asia, and the Middle East. Evidence of previous infection was defined as: Positive (household contact or positive polymerase chain reaction [PCR]/serology), Possible (suggestive clinical features of MIS-C and/or KD with negative PCR or serology but not both), Negative (negative PCR and serology and no known exposure), and Unknown (incomplete testing and no known exposure).

RESULTS

Of 2345 enrolled patients SARS-CoV-2 status was Positive for 1541 (66%) patients, Possible for 89 (4%), Negative for 404 (17%) and Unknown for 311 (13%). Clinical outcomes varied significantly among the groups, with more patients in the Positive/Possible groups presenting with shock, having admission to intensive care, receiving inotropic support, and having longer hospital stays. Regarding cardiac abnormalities, patients in the Positive/Possible groups had a higher prevalence of left ventricular dysfunction, and patients in the Negative and Unknown groups had more severe coronary artery abnormalities.

CONCLUSIONS

There appears to be a spectrum of clinical features from MIS-C to KD with a great deal of heterogeneity, and one primary differentiating factor is evidence for previous acute SARS-CoV-2 infection/exposure. SARS-CoV-2 Positive/Possible patients had more severe presentations and required more intensive management, with a greater likelihood of ventricular dysfunction but less severe coronary artery adverse outcomes, in keeping with MIS-C.

Classification and epidemiology of vasculitis: Emerging concepts

The recent publication of the American College of Rheumatology (ACR)-European Alliance of Associations for Rheumatology (EULAR) classification criteria for large vessel vasculitis and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) has provided modern criteria for the classification of these conditions, which incorporate contemporary methods of investigation and diagnosis. Further validation is required in independent cohorts, especially from populations that were not well represented in the development cohort. Studies of the occurrence of large vessel vasculitis report that Takayasu arteritis is a rare disease in most populations, and giant cell arteritis is the most common vasculitis in older populations. The incidence of AAV appears to have plateaued, but the prevalence is increasing as a result of lower mortality. The new classification criteria may affect the reported incidence and prevalence, and studies will be needed to confirm this. The impact of COVID-19 on the occurrence of the vasculitides is not completely known, but there is evidence of reduced occurrence of Kawasaki disease and IgA-associated vasculitis following lockdowns with reduced transmission of possible trigger infectious agents.

Spatiotemporal clusters of Kawasaki disease in South Korea from 2008 to 2017: A municipal-level ecological study

INTRODUCTION

As the etiology of Kawasaki disease (KD) remains unknown, identifying spatiotemporal clusters with proper stratification of KD could provide further evidence for investigating the triggers of KD. However, spatiotemporal distributions of KD with sex stratification have never been reported. Therefore, we aimed to analyze the spatiotemporal patterns of KD by sex in South Korea.

METHODS

We extracted epidemiologic week (Epiweek)-based KD cases in patients <5 years of age (ICD-10-CM code: M303) from 2008 to 2017 national health insurance service data at the 250 municipal level. To determine whether spatial autocorrelation and persistent municipal-level clusters exist, year- and sex-stratified global Moran's I statistics, Getis-Ord Gi* statistics, and emerging hotspot analysis on KD incidence were conducted.

RESULTS

A total of 72,510 KD cases were reported between 2008 and 2017 (male-to-female ratio = 1.40:1). Incidence has increased since 2008, with the highest incidence in 2016 (396.8 per 100,000 population). KD had seasonality of winter and summer but different by sex. Positive spatial autocorrelation was consistently reported in every stratum, with the 2011-2014 period having the strongest index value (total sex I = 0.286, p < 0.001; male I = 0.242, p < 0.001; female I = 0.213, p < 0.001). Hot spots were consistently detected in the northern parts, and cold spots were in the southern part for 9 years in both sexes. The emerging hot spot analysis showed new, consecutive, and sporadic hot spots on the northwestern and eastern coasts and new and sporadic cold spots in the southwestern part. However, the distribution and proportion of hot or cold spot types differed according to sex.

DISCUSSION

The spatiotemporal features of KD had limits to concluding that only infectious triggers result in KD occurrence. Therefore, our findings support the notion that KD is a syndrome with multiple factors, including infectious, genetic, and environmental factors, that are associated with sex differences.