Fig. 1.

Structure and modifications of recommendations in the updated guideline. Note: Unchanged recommendation, the main content and the strength of recommendation remain unchanged relative to the original recommendation; modified recommendation, the main content or strength of the recommendation has been changed from the original recommendation; new recommendation, the recommendation that was not included in the original version of the guideline has been added during the update; unpreserved recommendation, the recommendation in the original version of the guideline has not been preserved in the updated guideline. Abbreviations and acronyms: COVID-19, coronavirus disease 2019; MIS-C, multisystem inflammatory syndrome in children; HFNC, high-flow oxygen by nasal cannula; NIV, non-invasive ventilation; AHRF, acute hypoxemic respiratory failure