A lot of the stuff we vax for isn't even that dangerous. The shot that is causing the biggest uproar right now...the MMR combo...vaccinates against three diseases that are rarely, if ever, fatal. In fact, rubella symptoms are so mild that your kid can have it and you don't even realize it. But it can cause birth defects if a pregnant woman catches the disease, so we routinely vaccinate everyone to keep it under control for the sake of the unborn. Unfortunately, the MMR vaccine has been linked to problems for lots of kids and they think its might be the cause of the sudden spike in autism rates in the US. The solution is pretty simple: instead of a combo shot, you give the three vaccines separately over the course of a few months and that reduces the risks immensely. But its less convenient for doctors and the drug companies push the combo shot to the point where its difficult to even get the individual doses without a bunch of rigamarole. So families panic and don't vaccinate at all and that's pretty scary too.