“All that is known about the mysterious illness comes from the letter Vivaldi wrote asking for the dispensation, in which he referred to it as a ‘tightness of the chest.’
“According to White, ‘it would have been very hard for Vivaldi to give up saying Mass. It would have been his own decision, a decision of nobody but himself, and he also gave up a good salary.’
“She pointed to rumors alleging that he had been kicked out of the priesthood or even excommunicated, saying they ‘are so ignorant and so stupid,’ because if one looks to the facts, the rumors are ‘not proven.’
“She also addressed rumors that Vivaldi had abused the choir girls as the reason he was kicked off the Pieta faculty in 1715. These rumors, she said, ‘not only are they not true, but also they’re impossible.’
“Not only would Vivaldi have never been welcomed back in 1723, but also many of the girls who remained in the orchestra stayed until they were 70 or even 80 years old.
“The hospital was also overseen by several governors, so had there been abuse, Vivaldi would have been kicked out right away, ‘so that doesn't add up,’ White said.”
[slightly edited to fix grammatical errors]
By Elise Harris, Catholic News Agency
Interview with Micky White, author of Antonio Vivaldi: A Life in Documents
https://www.catholicnewsagency.com/news/36556/what-makes-vivaldi-unique-among-composers-he-was-a-priest
It is conceivable that his asthma was debilitating enough to prompt a decision. Latin Mass is long, and a priest must be moving about, from side to side, to the communion rail and back, and so forth. Maybe God chose musical genius. (b. 1678 Venice, d. 1741 Vienna)