COVID-19 and its impact on allergic and immunologic diseases in childrenAt the time of writing this editorial (beginning of May 2020), the world has already been facing for several months a major health threat with unprecedented societal changes. The changes were and will continue to be so unpredictable that it is difficult to anticipate what constraints we will be facing at the time you will be reading this editorial. Hopefully, the pandemic will be under control. The new coronavirus, the SARS-CoV-2, has granted us a new, multifaceted disease that started as an infectious disease, but has now become a much higher burden due to acute or post-acute inflammatory events. Pediatric Allergy and Immunology is lucky to have committed contributors who were able to very quickly write articles either for clinical guidance or to update our knowledge, as well as to provide a hypothesis for the mechanisms of infection. The result is this thematic issue focusing on COVID-19. The issue starts with the recommendations from the EAACI pediatric section on the management of allergies and immunodeficiencies during the pandemic. 1 The next article by Lu and colleagues explains what immune mechanisms are behind COVID-19 according to the literature to date. 2 This first section ends with Matricardi, Negro, and Nisini developing an interesting hypothesis for the spreading of COVID-19 based on the viral load and barrier factors. 3 Two further contributions related to COVID-19 come later in this issue. The first reports on the outbreak of COVID-19 among health providers in the perinatal center of a largeGerman hospital, 4 and the second on two patients with X-linked agammaglobulinemia, suggesting that B cell response might be important, but not strictly required to overcome the disease. 5