@cholash Yes, questions above my pay grade, too, but I will offer this opinion expressed by my ID doctor who has conducted a lot of studies (Kevin Winthrop of OHSU). When I asked about drinking water, brushing my teeth, showering and such, he said (paraphrasing), “That’s what the nebulizing saline and airway clearance are for. The bacteria is everywhere and going to get in there, but by doing those things you help prevent their taking hold and establishing an infection. Drink the water, take short showers in a well ventilated room, wear a mask when gardening, wet the soil to keep the dust down, and have somebody else empty bags of amendments when you’re not around. Then be sure to nebulize and clear the airways to prevent the bacteria from taking up residence.” My life stall doesn’t involve large crowds or close quarters, but if it did I would mask. I already have MAC, so I can’t be sure I’ve prevented anything, but it hasn’t grown significantly. The only exacerbation I’ve had (untreated) was the result of a sinus infection. I’d say I’m moderate in the precautions I take, but faithful to the prevention part.