Grade 1: mild transient reaction; infusion interruption not indicated; intervention not indicated

Grade 2: therapy or infusion interruption indicated but responds promptly to symptomatic treatment (e.g., antihistamines, NSAIDS, narcotics, IV fluids); prophylactic medications indicated for <=24 hrs

Grade 3: prolonged (e.g., not rapidly responsive to symptomatic medication and/or brief interruption of infusion); recurrence of symptoms following initial improvement; hospitalisation indicated for clinical sequelae

Grade 4: life-threatening consequences; urgent intervention indicated

Reference: Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 Published: November 27, 2017