Hi, lvnl,
I have bronchiectasis and not MAC. The combination of Albuterol Nebs and the SmartVest was effective for me within the first 2 months. I was able to clear sputum from both treatments pretty much right away. It has gotten better using both treatments twice a day. I have learned to use them together sometimes doing one first and then the other. Does your vest fit very securely ? Hope this helps!