More than 3,000 restaurant patrons in Fayetteville, North Carolina, have been immunized for hepatitis A after an Olive Garden employee told management that he’d tested positive for the virus, Food Service News reports. The Cumberland County Health Department and nearby Fort Bragg established free walk-in clinics for those who visited the restaurant during an eight-day period in late July and early August. Thus far, no new cases of hepatitis A have been linked to the incident.

Health department officials stated that the treatment-including both the hepatitis A vaccine and immune globulin-is only effective if administered within two weeks of exposure.

Hepatitis A is spread through food contaminated by human waste. In the case of restaurants, consumers may be infected when a worker with hepatitis A handles food after failing to wash his or her hands properly when using the bathroom. Hepatitis A infection results in swelling of the liver; symptoms can include joint pain, fever and nausea, though mild infections with little to no symptoms are common. Unlike hepatitis B and C, hepatitis A rarely has long-term health effects and often clears up on its own within two months.