EURweb reports that the actress is suffering inflamed vocal chords.
"No one is more frustrated and disappointed than she is that will be out the show through the end of June, but she must adhere to her doctor's orders," her rep said in a statement.
"One of the joys of being a mother is that your children bring home a diverse array of germs from school, making one more prone to illness," the statement continued. "Unfortunately, Audra has been struck down a couple of times during the run of this production, and she cannot perform a role as vocally demanding as Bess when she's ill."
McDonald has already missed several performances, leaving ticket holders angry, according to the New York Daily News.
McDonald is just as upset as fans. The actress tweeted, "Want to scream but not allowed to speak. Spent last few days at the doctor's having mirrors and cameras shoved down my throat and what it comes to is this: I have to shut up. I miss the show. I miss the cast. I miss being able to speak to my family. But doctors orders, so I shut up until I heal."