There's a new paradigm shift in medicine the last few years that says that it's actually better to be constantly exposed to new pathogens because it causes your body to have to fight it and adapt to it. It's that constant cycle of exposure and adaptation that makes the body stronger.
This is kinda disgusting , but there is a doctor in Australia that says that eating your boogers can actually make your immune system stronger and help keep you from getting sick. The basic idea is that pathogens are trapped in the mucus in the nose, and when they are eaten they are weakened by the digestive tract. This allows the body to develop antibodies and other adaptations to the weakened pathogens without ever having to be exposed to a healthy pathogen that might make you sick. It's a controversial idea, but it's getting traction within the medical community.
