The coronavirus disease 2019 (COVID-19) pandemic has inflicted a considerable pressure on populations, healthcare systems and community organisations worldwide, due to the fast spread of the disease and its huge global burden of morbidity and mortality, healthcare resource consumption, and societal and economic implications [1]. Since its appearance in December 2019, it has become rapidly obvious that this new disease behaves very differently from previously known viral pneumonias in terms of risk factors, biological, radiological and clinical presentation, natural course and response to therapy [2], making specific research and clinical guidance mandatory to understand the disease, deliver appropriate care and support public health decisions. Although the clinical picture is very heterogeneous, the potential for severe life-threatening conditions in adults comes from the respiratory component of the disease: airways, alveolar and vascular damage, inflammation, dysfunction and repair can lead to rapidly progressive acute hypoxemic respiratory failure [3]. As yet inexplicably, the manifestations of COVID-19 are very different in children and young people, with the respiratory illness usually being trivial, but a rare, severe Kawasaki-like vasculitic illness has been described [4]. Since respiratory failure is the main determinant of short-term prognosis in adults, it should be a top priority for research and development of clinical guidance. Underlying mechanisms include a