Immune systems nowadays are overworked, not underworked. Antibiotics themselves suppress our immune systems by killing the good bacteria in our g.I. tract and irritating/inflaming it... then there's the other meds, insecticides, herbicides, artificial colors, preservatives, and other chemicals in our food, various forms of stress, poor nutrition, unrealized food allergies, and more.... taxing our immune systems like never before. Wood dust ain't no good for us either :^)