Human trials of a cholesterol-lowering vaccine to help prevent heart disease are underway after successful studies on mice. <br/><br/>Researchers at the Medical University of Vienna are testing the safety of their experimental treatment in 72 volunteers. <br/><br/>The jab is designed to stop fatty deposits from clogging the arteries. It would offer patients an alternative to taking daily pills to cut their risk of stroke, angina and heart attacks.<br/>