Medical researchers study diseases and other physical conditions that affect humans in order to improve treatment options or lessen the incidence of some diseases. Through medical research, new vaccines, treatment protocols and medicines are developed, and links between certain behaviors and diseases are identified. Medical researchers work for research labs at hospitals and universities, pharmaceutical companies and government agencies. They require extensive graduate level education, but usually have greater job stability than those in other occupations because they are generally at work on long-term research projects.