A preventative maneuver is an action that decreases the risk of a future event or the threatened onset of disease. Primary prevention is designed to stop a condition from developing. Secondary prevention is designed to stop or slow progression of a disease or disorder when patients have a disease and are at risk for developing something related to their current disease. Very often secondary prevention is indistinguishable from treatment. An example of primary prevention is vaccination for pertussis; an example of secondary prevention is administration of an anti-osteoporosis intervention to women with low bone density and evidence of a vertebral fracture to prevent subsequent fractures. An example of tertiary prevention is a rehabilitation program for patients suffering the adverse effects associated with a myocardial infarction.