Hey, Roberta. Merry Christmas. Initials and acronyms differ, do they not?
There used to be a hard and fast rule, that should a writer begin with initials and acronyms, the explanation appeared in parentheses. There after, the acronym or initials could be used.
WHO- (world health organization)
RAM-(random access memory)
WMD-(weapons of mass destruction)
Sorry if I have overstated my case (OMC)