If everyone, all around the world, stayed in their houses for 2 weeks, and didn't come out, didn't interact at all. As long as everyone had only a few people in their house, wouldn't cold, flu etc all just become extinct? (Ditto chicken pox, measles etc. Not malaria, dengue fever, and a few others, but still!)
I know it's totally not a realistic plan. But it would work, right?