Comment:

The Allergy/Intolerance resource has again consumed the Reaction resource. It is possible to have a Reaction that is more complex than an Observation (because it is associated with a substance) but that is associated with a situation rather than a patient-specific propensity. The FDA Adverse Event Report is a very heavy object, and should not be expected to serve clinical requirements. Perhaps the intent is to create a third Reaction class for such events ("A reaction to an exposure not associated with a patient-specific propensity to reaction, but rather with a circumstantial cause such as a drug interaction."), but as it stands, Reaction is unacceptable.