Stanford University researchers have discovered a way to create a pain-free vaccine that can be applied as a cream to the skin, using a harmless bacteria called Staphylococcus epidermidis, which naturally lives on everyone’s skin. This bacteria triggers the body’s immune system to produce antibodies, just like a regular vaccine would. The team has even engineered this bacteria to protect against dangerous diseases like tetanus and diphtheria. While this technology has the potential to revolutio...