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

Abstract

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.

Keywords: Kawasaki disease; coronavirus disease-2019 pandemic; etiology; pediatric infectious disease.

Figure 2

Differences in weekly trends in the numbers of patients with Kawasaki disease and PIDs between 2020 and 2017-2019. Numbers of patients who developed Kawasaki disease and PIDs in 2017–2019 are presented as mean and range for each week using error bars. The school closure period (weeks 10-19) is highlighted using dashed lines in all panels.

Figure 3

Comparison of weekly trends in the number of patients with complete and incomplete Kawasaki disease between 2020 and 2017-2019. The numbers of patients who developed complete and incomplete Kawasaki disease in 2017-2019 are presented as mean and range for each week using error bars. The school closure period (weeks 10-19) is highlighted using dashed lines in all panels.

Figure 5

Correlation between percent reductions in the weekly numbers of patients with Kawasaki disease and those with PIDs in 2020. The percent reduction in the number of patients for each disease in 2020 were evaluated to compare mean patient numbers for these diseases in 2017-2019. ∗ Significant correlation.

Figure 1

Selection of hospitals and patients with Kawasaki disease. ∗Potentially incomplete reporting information during 2020.

Figure 4

Percent reduction in the weekly numbers of patients with Kawasaki disease and PIDs in 2020 compared with 2017-2019. The mean and range of weekly percent reductions in the numbers of patients who developed Kawasaki disease and PIDs are compared between 2020 and 2017-2019, shown using error bars in the charts. The school closure period (weeks 10-19) is highlighted using dashed lines in all panels.