@amelia We are the same age. I have been coughing for over 20 years. Many years ago when I was in graduate school, a chest X-ray showed scarring in my lungs and a skin test for TB was positive. Then sputum samples were ordered because of positive skin test. But the test came back negative. The conclusion was that I was exposed to TB bacteria when I was a child. Although I never developed TB, my lungs were scarred because of the exposure. Many years later, my pulmonologist suspects that I got bronchiectasis from scarred lungs and MAC from bronchiectasis. I have not read any report on mortality of MAC and I don't intend to. My pulmonologist and I have decided that I will go to see him every 12 months or as needed if I start to feel worse, to monitor any development in my lungs. But after the big scare of coughing up large amount of blood and spending the night in the ER a few years ago, there has no any such incident since. Each chest X-ray or CT scan continues to show the scarring in my lungs but also show gradual improvement in the cloudiness that showed up when I was first diagnosed with MAC. And as I said before, I feel great and live a very active life. Besides playing tennis regularly, I just came back from a trip out west where my husband and I hiked a 14-mile (round trip) mountain trail with 4,000 feet elevation gain that took us to a height of 11,000 feet above sea level. For this reason, I believe I'm in the clear for as long as my chest X-ray and CT scan do not show worsening condition. As far as I know, if you don't have other underlying lung disease or compromised immune system, it is possible that MAC can clear without treatment. If it's not, you will know because things will worsen. So you'll only worry about it if/when that happens. I'm borrowing @windwalker Terri's motto to wrap up my answer, "Don’t let the worries of tomorrow steal from the joys of today". That is exactly what I live by but can't verbalize it as well as Terri does. So if you are feeling fine, don't let this thing called MAC steal your thunder. At our age, slowing down is a given.