An adverse event (AE) is called serious if it:
- results in death,
- is life-threatening (at risk of death at the time of the adverse event, not an event which ‘could’ hypothetically have caused death if it were more severe),
- requires hospitalisation or extension of existing inpatients’ hospitalisation,
- results in a persistent or significate disability or incapacity, or
- is a congenital anomaly or birth defect.
Other events such as those requiring emergency intervention to prevent one of the serious outcomes described above might also be reported as a serious adverse event.