Right. They didn't want to give a title to a death for which they really didn't know the cause, so it was becoming, maybe, a bit easy just to say...I don't want to say “easy”, but SIDS was a misnomer because there really was no definitive cause of death that they could figure out, so “unknown” was a better term, I guess.
On November 22nd, 2018. See this statement in context.