I've never heard or read about the link to ear infections. But I honestly remember one time reading a post someplace here about cannabis smoke being used as a treatment for open wounds and skin infections (because of its antibiotic and anti-inflammatory properties). I think the jury's still out on that treatment because it hasn't been formally tested--and because the little moisture droplets that come our with our breath tend to be loaded with microbes. I'm guessing there's probably not been a formal link yet established between second-hand weed smoke and ear infections, unlike cig smoke, which has had a lot more "market testing."