A food handler at the McDonald's Restaurant in Milan, Illinois, was hospitalized on June 16 for what subsequently was diagnosed as hepatitis A. The food handler stated that she told her employer, on June 25, about the illness and returned to work. The Rock Island County Health Department stated that they received the first report of hepatitis A related to the restaurant on July 10. They also stated that they did not know of the first food handler's illness, in June, until they had received a report in the mail on July 19. Reports of hepatitis A are immediately reportable by telephone in Illinois. The management of the Milan McDonald's stated that July 13 was the first time that they were notified of the hepatitis A outbreak. Additional reports of hepatitis A came in from the general community throughout the first three weeks of July, including a report regarding another foodworker from the same restaurant. The health department decided to offer vaccination on July 15, but did not begin to provide public vaccination clinics until July 21; at least 5324 people were subsequently vaccinated by August 3. Based on store receipts, perhaps as many as 10000 people were exposed to hepatitis A.