The increased incidence in Kawasaki-like disease identified in children in Italy may be associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and other countries should expect a similar Kawasaki-like disease outbreak, according to the results of a study recently published in The Lancet

The SARS-CoV-2 epidemic, causing coronavirus disease 2019 (COVID-19), spread worldwide, with the residents of Italy being significantly affected in February 2020. Although COVID-19 in adults is characterized by severe pneumonia and hyperactivation of the inflammatory cascade, respiratory involvement in children is usually not as severe.

Kawasaki disease, which was first reported in Japan approximately 50 years ago, is an acute, self-limiting vasculitis of the coronary arteries that seems to exclusively affect otherwise healthy young infants and children. In the acute phase of this disease, patients may have hemodynamic instability, also known as Kawasaki shock syndrome, or they may experience macrophage activation syndrome that resembles secondary hemophagocytic lymphohistiocytosis. Although the etiology of Kawasaki disease remains unknown, evidence suggests that an infectious agent may trigger a cascade that causes this illness. This observational cohort study was conducted to evaluate the incidence and features of patients with Kawasaki-like disease diagnosed during the SARS-CoV-2 epidemic.

In total, 29 Italian children patients diagnosed with Kawasaki-like disease in the past 5 years were included. Patients were divided into 2 groups according to symptomatic presentation before (group 1; n=19) or after (group 2; n=10) the beginning of the SARS-CoV-2 pandemic. Group 1 comprised 7 boys and 12 girls with a mean age of 3.0 years who were diagnosed between January 15, 2015, and February 17, 2020. Group 2 comprised 7 boys and 3 girls with a mean age of 7.5 years who were diagnosed between February 18, 2020, and April 20, 2020. Real-time polymerase chain reaction testing of nasopharyngeal and oropharyngeal swabs was used to confirm current or previous infection, and serologic qualitative testing was performed to detect SARS-CoV-2 immunoglobulin M (IgM) and IgG. Kawasaki disease shock syndrome was defined by the presence of circulatory dysfunction, and macrophage activation syndrome was determined based on Pediatric Rheumatology International Trials Organization criteria.


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Eight (80.0%) of the 10 patients in group 2 tested positive for IgG, IgM, or both. Significant differences noted between group 1 and group 2 include disease incidence (0.3 vs 10 per month), mean age (3.0 vs 7.5 years), Kawasaki disease shock syndrome (0% vs 50%), cardiac involvement (10.5% vs 60%), macrophage activation syndrome (0% vs 50%), and the need for adjunctive steroid treatment (15.8% vs 80%; P <.01 for all categories).

These results suggest that the 30-fold increased incidence in Kawasaki-like disease reported in April 2020 is associated with the SARS-CoV-2 pandemic. The study authors conclude that “A similar outbreak of Kawasaki-like disease is expected in countries involved in the SARS-CoV-2 epidemic.”

Reference

Verdoni L, Mazza A, Gervasoni A, et al. An outbreak of severe Kawasaki-like disease at the Italian epicenter of the SARS-CoV-2 epidemic: an observational cohort study. Lancet. doi:10.1016/S0140-6736(20)31103-X