Again Dr. Nevin has written papers on the screening, and it's really quite simple: Have you been exposed to this medication, and did you have this reaction to it? It's as simple as that in terms of understanding. Now we're identifying those who had that prodromal reaction—which is to say the symptoms that appeared when they were on the medication—which then sets them at risk of having persistent reactions.
On April 29th, 2019. See this statement in context.