I often wondered when Merman had that throat problem in GYPSY. Was it shortly after the cast album session? Doing 3-4 takes of "roses Turn" alone would bust anyone's blood vessel.
It is true, however, that Merman rarely missed a performance due to illness and never just took random sick days. Legend has it she missed a few performances in SOMETHING FOR THE BOYS due to laryngitis, and a week from GYPSY. That's about all.
Also the 5-week shutdown of GYPSY afforded Merman a well-earned vacation, but also gave them time to move the show from the Broadway over to the Imperial. It’s possible that taking a 5-week break in the middle of the summer tourist season hurt the show’s momentum at the box office.
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com