@bolso1 Unfortunately, the BCG vaccine is much less effective on older adults: "There's no evidence the BCG vaccine works for people over the age of 35." https://www.nhs.uk/conditions/vaccinations/when-is-bcg-tb-vaccine-needed/ and https://www.cdc.gov/tb/publications/factsheets/prevention/bcg.htm

Btw, if you'll notice from Terri's (@windwalker) comments above on various likely places one is exposed to MAC, the members of this forum have been doing lots of research on various aspects of MAC and bronchiectasis over the years. Terri alerted us (and many doctors) to the efficacy of nebulizing with 7% saline to help kill off MAC. @windwalker can give you links to the articles she's given us on that topic.