The quotation from The Epidemics indicates that early Greek physicians had the dual responsibilities of helping and not harming their patients. These responsibilities have become two of the pillars of modern medical ethics-the principles of beneficence and nonmaleficence. Zenophon's words challenge physicians to expand their concept of "helping" and "doing no harm" beyond the pedestrian calling of therapeutics to the far nobler calling of prevention. As a hospital epidemiologist, I would agree with Zenophon, and I would argue that we physicians best fulfill our moral responsibilities of beneficence and nonmaleficence when we practice prevention. Yet, from Semmelweis' time to the present, prevention has not been regarded as a noble calling. It has been, instead, relegated to "the back seat" with respect to the flashier, more technological pursuits of diagnostics and therapeutics. In medicine as in Greek mythology, we frequently neglect to keep the jar's lid tightly closed and choose instead to confront pestilence only after it has escaped. Influenza viruses cause respiratory illness that in particular individuals may be complicated by pneumonia, cardiac failure, and death. Major epidemics in the United States are associated with twofold to fivefold increased rates of hospitalization for adults with highrisk medical conditions' and with 10,000 to 40,000 excess deaths.1,2 The vast majority of these deaths occur in persons over the age of 65 years. Furthermore, estimates of the economic loss from influenza in the United States have ranged from $1 to $10 billion per year.2,3 To paraphrase a 20th century lay philosopher, "If that's not harm, what is?" Despite the grim statistics and the yearly recommendations by the Centers for Disease Control and Prevention, healthcare workers are remiss in using the influenza vaccine-only 30% of both high-risk patients2 and healthcare workers receive the vaccine.4 In their article, Watanakunakorn and coworkers4 report additional disturbing observations. First, the major reasons for not receiving the vaccine ("I heard it had bad side effects," "I do not like shots," "I had bad side effects from flu shots in the past," "I thought the flu shots did not work," "I did not know I needed a flu shot," etc.) indicated that misinformation and narcissism, not concern for the welfare of patients, motivated many decisions. Second, education had little effect on vaccination rates and on the attitudes of healthcare workers regarding the vaccine. Although shocking for a profession that prides itself on the acquisition of knowledge, this observation does not surprise hospital epidemiologists given the poor compliance with simple practices such as handwashing5,6 and isolation precautions.7 The observations of Watanakunakorn and coworkers support the conclusion of Wenzel and Pfaller that information alone is inadequate to alter behavior optimally.8 Given their exposure to numerous sick persons, healthcare workers might be at high risk of acquiring