Verdoni and colleagues wrote an interesting paper aimed to investigate the clinical features and the incidence of Kawasaki-like disease during SARS-CoV-2 outbreak. The authors reported a 30-fold increased incidence of Kawasaki-like disease in Bergamo (North Italy) from Feb 18 to April 20, 2020 in comparison to the previous 5 years. Children diagnosed after the SARS-CoV-2 epidemic began also presented difference clinical features (older patients, more frequent cardiac complications, more frequently MAS). In some of those patients, evidence of SARS-CoV-2 infection was found.

The manuscript is of great importance since it showed that also children may present severe complications of COVID-19, such as KD-like disease, which has been rarely descrideb so far, and makes aware the scientific community that an increase of KD and KD-like disease in children should be expected in case of extension of COVID-19 epidemic.

The article is very well-written and easily readable. The methods and results are clear. Yet, I have a major concern which may affect the effectiveness of the study. The authors used the Student’s t test in order to compare the continuous variables between the two groups of patients. The Student’s t test is a parametric test which fits for continuous variables with a Gaussian distribution. In case of application of parametric tests to variables with not-normal distribution, the results can be not reliable. Yet, the authors should clearly declare the distribution of the continuous variables and, in case of not-normal distribution, should use non-parametric tests in order to compare the two groups, such as Mann-Whitney U test.