it isn't ALWAYS yes anymore, but one real issue with vaccines is, they want to give your child 4-5 at a time. Each (most) has an adjuvant, which "supercharges" ones immune system. 1 adjuvant does that, but now inject 5 doses and now you have created an autoimmune dysfunction, which accounts for a large part of vaccine injury. There is a reason they never "test" multiple vaccines in conjunction, but administer them in conjunction. They know perfectly well
In a schematic, a "v" usually represents a diode, which only lets electricity flow one direction (effectively turning a/c into dc, but could be another component, depending on what it actually looked like). If you had and ACTUAL picture, I could probably tell you what it is doing.