BCG vaccine is interesting. although primarily antitubercular it is apparently about moderately useful against a variety of illnesses (pubmed references). Mice get about 1/3 less atherosclerosis. If a moderate reduction of risk of 5 things of value with one immunization. The thing is that BCG causes a scar. Those people with "arm circles" likely got one. with BCG interior to the belly button, or possibly the scalp, people would gain the multidisease decrease benefits without a visible scar.
Although more research would be beneficial BCG reduces atherosclerosis, some cancers, and some cardiac things (pubmed)-- beanangel, Jan 13 2017random, halfbakery