Kawasaki disease in siblings in close temporal proximity to each other-what are the implications?

Association of Kawasaki disease with urbanization level and family characteristics in Taiwan: A nested case-control study using national-level data

Kawasaki disease (KD) is an inflammatory vasculitis disorder of unknown etiology. It is a rare but fatal disease and the leading cause of acquired coronary heart disease in children under the age of 5 years. We examined the association of KD with the demographics of family members, parents' characteristics, and perinatal factors in Taiwanese children. This nested case-control study used data from Taiwan's Health and Welfare Data Science Center and initially included children born in Taiwan between January 1, 2006, and December 31, 2015 (n = 1,939,449); the children were observed for KD development before the age of 5 years (n = 7870). The control group consisted of children without KD who were matched with each KD case by sex and birth date at a ratio of 8:1. The odds ratio (ORs) of the aforementioned associations were estimated using conditional logistic regression. The risk of KD decreased in children with younger parents [<25 years; younger maternal age, OR = 0.72, 95% confidence interval (CI), 0.66-0.79; younger paternal age, OR = 0.68, 95% CI, 0.59-0.78], lower socioeconomic status, more than 2 siblings (OR = 0.80, 95% CI, 0.73-0.89), and siblings with a history of KD (OR = 4.39, 95% CI, 3.29-5.86). Children living in suburban (OR = 0.95, 95% CI, 0.90-1.00) and rural (OR = 0.81, 95%CI, 0.74-0.90) areas exhibited a lower risk of KD than children living in urban areas. In conclusion, a higher incidence rate of KD was observed in children aged <5 years who had an urban lifestyle, had siblings with KD, were born to older mothers, and belonged to high-income and smaller families. Parental allergic or autoimmune diseases were not associated with the risk of KD.

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).

Incidence of Kawasaki Disease Before and After the COVID-19 Pandemic in Japan: Results of the 26th Nationwide Survey, 2019 to 2020

IMPORTANCE

Global studies have reported that the incidence of Kawasaki disease (KD) declined during the COVID-19 pandemic. These studies suggest that the global pandemic and its accompanying mitigation measures may provide an important opportunity to explore the hypothesis of a KD pathogenesis.

OBJECTIVE

To compare changes in KD incidence in Japan before and after the start of the COVID-19 pandemic.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted using the data set from Japan's 26th nationwide KD survey that obtained information on patients who were diagnosed with KD in Japan from January 1, 2019, through December 31, 2020.

MAIN OUTCOMES AND MEASURES

Kawasaki disease incidence rates were calculated by referring to the national population data in the vital statistics data for Japan.

RESULTS

A total of 28 520 patients were identified (16 236 male individuals [56.9%]; median [IQR] age, 26 [14-44] months). A total of 17 347 patients were diagnosed with KD in 2019 and 11 173 were diagnosed in 2020, representing a 35.6% reduction in the number of patients diagnosed in 2020 compared with the previous year. Patient distributions for days of illness at the first hospital visit were almost identical in 2019 and 2020, suggesting that the decrease in KD incidence likely was not associated with pandemic-related delays in seeking treatment. The proportion of patients diagnosed with KD who were younger than 12 months was significantly larger in 2020 than in 2019 (21.6% vs 19.4%; P < .001). Compared with KD incidence among younger patients, the incidence among those 24 months and older declined rapidly after initiation of COVID-19 special mitigation measures, with a greater percentage reduction (58.3% reduction in July), but rebounded faster after the end of the special mitigation period. By contrast, the incidence among patients younger than 12 months declined moderately after the initiation of the special mitigation period, with a lower percentage reduction (40.3% reduction in October), and rebounded at a later phase.

CONCLUSIONS AND RELEVANCE

In this cohort study, the number of patients diagnosed with KD decreased by approximately one-third across Japan in 2020, with no indication that parents avoided a hospital visit. Differences in KD incidence reduction patterns before and after the initiation of COVID-19 pandemic mitigation measures were found in patients with KD aged younger than 12 months compared with those 24 months or older, suggesting a potential KD pathogenesis involving transmission among children.

Regional Differences in Kawasaki Disease Incidence Reduction Before and After the Onset of the Coronavirus Disease 2019 Pandemic

OBJECTIVE

To assess regional differences in reduction of the incidence of Kawasaki disease during the mitigation period for the coronavirus disease 2019 pandemic, with a hypothesis that more sparsely populated regions have fewer opportunities for human-to-human contact, resulting in a greater reduction in the incidence of Kawasaki disease.

STUDY DESIGN

A retrospective ecological study was conducted using data from patients hospitalized for Kawasaki disease as well as infectious diseases surveillance reports in Shiga Prefecture, Japan, during 2015-2020. We defined the periods before and after the onset of pandemic as January 2015-March 2020 and as April 2020-December 2020, respectively. We compared the reductions in the incidence of Kawasaki disease among 6 administrative regions in the prefecture according to the density of the populations.

RESULTS

A total of 1290 patients with Kawasaki disease were identified. The incidence of Kawasaki disease (per 100 000 person-years) was significantly reduced after the coronavirus disease 2019 pandemic onset (period before pandemic onset, 105.6 [95% CI 99.8-111.8]; period after pandemic onset, 68.6 [95% CI 56.7-83.0]). During the period after pandemic onset, the incidence of Kawasaki disease was significantly reduced in May, compared with the corresponding period in previous years. The number of patients aged 2-4 years was significantly reduced after the pandemic onset. Notably, greater reductions in the incidence of Kawasaki disease were found in regions with lower population densities.

CONCLUSIONS

Assuming that there were fewer opportunities for human-to-human contact in more sparsely populated regions during the pandemic mitigation period, our findings support the hypothesis that human-to-human contact may be associated with development of Kawasaki disease.

Kawasaki Disease: Pathology, Risks, and Management

Kawasaki disease (KD), first reported as an acute febrile mucocutaneous lymph node syndrome, is a self-limiting vasculitis of unknown etiology. The most important aspect of KD is the prevention of coronary artery lesion (CAL) because myocardial ischemia or infarction due to CAL might be lethal. In addition to the CAL, patients with KD develop systemic vasculitis, which indicates the presence of vascular endothelial damage. Studies assessing pulse wave velocity or percentage change in flow-mediated dilatation have shown that aortic stiffness is increased in patients with KD history. In contrast, the cardio-ankle vascular index, a novel parameter not affected by blood pressure, has not demonstrated increased aortic stiffness in patients with KD. Although many studies using various parameters have suggested a risk of atherosclerosis in patients with a history of KD, a few others have reported no significant differences between KD patients and controls. Therefore, it will be necessary to thoroughly understand the characteristics of each parameter, before evaluating the results of those studies, to understand systemic vascular dysfunction in these populations, and to manage their vascular health. Although it is controversial whether the risk of atherosclerosis in patients with KD is higher, those with CAL are thought to be at a high risk of atherosclerosis. Therefore, appropriate treatment to prevent CAL in the acute phase and subsequent regular follow-up is important. Here, we review the pathology, risk, and management of vascular disorders, especially systemic vascular disorders, in patients with KD history.

Kawasaki Disease and Pediatric Infectious Diseases During the Coronavirus Disease 2019 Pandemic

OBJECTIVE

To assess the epidemiologic association between Kawasaki disease and common pediatric infectious diseases (PIDs) identified during the coronavirus disease 2019 (COVID-19) pandemic period to confirm whether the infection-triggered theory is a plausible hypothesis for the pathogenesis of Kawasaki disease.

STUDY DESIGN

A retrospective epidemiologic study was conducted using datasets obtained from Web-based surveillance of Kawasaki disease and PIDs in Japan. We compared weekly numbers of patients who developed Kawasaki disease and specific PIDs between 2020 and 2017-2019 and evaluated the association between the percent reduction in the number of patients with these diseases.

RESULTS

A total of 868 patients developed Kawasaki disease in 2020. During the social distancing period in 2020, the number of patients with Kawasaki disease was approximately 35% lower than in 2017-2019. Time from the onset of Kawasaki disease until the first hospital visit did not differ significantly among the examined years. The proportion of older children with Kawasaki disease decreased more than that of infants with Kawasaki disease (age <1 year), resulting in a significant difference in the proportion of infant patients between 2020 and 2017-2019 (24% vs 19%; P < .01). The number of patients with incomplete Kawasaki disease was unchanged from that of previous years. The weekly percent reduction in patient numbers differed between Kawasaki disease and PIDs during 2020, with no strong correlation between the 2 diseases.

CONCLUSIONS

Our data indicate that parents of patients with Kawasaki disease did not avoid hospital visits during the COVID-19 pandemic period. The findings indicate the possibility that triggering Kawasaki disease might be associated with presently unidentified respiratory pathogen(s) that potentially might be acquired from both within and outside the household.

Multisystem inflammatory syndrome in children (MIS-C) occurring in temporal proximity between siblings

We report a pair of siblings who developed multisystem inflammatory syndrome in children (MIS-C) in close temporal proximity after recent exposure to SARS-CoV-2. Both siblings presented with Kawasaki disease-like features and haemodynamic instability, with the onset of symptoms within 6 days of each other. Remarkably, one of the siblings was the elder of a pair of monozygotic twins. The younger monozygotic twin, however, did not develop MIS-C.

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.