During most influenza seasons, 10% to 20% of the nation’s population is infected with influenza with an annual estimated cost of approximately $10 billion. During severe epidemics, estimated cost may be as high as $12 billion.
Source: Williams WW, Hickson MA, Kane MA, Kendal AP, Spika JS, Hinman AR. Immunization policies and vaccine coverage among adults: the risk for missed opportunities. Ann Intern Med 1988;108:616-625.