CONCORD, N.H. — Up to 1,000 patrons of an American Legion hall and restaurant in Hopkinton are being asked to get vaccinated against hepatitis A after a bartender was diagnosed with the contagious liver disease.

Hepatitis A illnesses occur within 15 to 50 days of exposure to the virus and can last from a few weeks to several months. Symptoms include fatigue, abdominal pain, jaundice, abnormal liver tests, dark urine and pale stool.

If given soon after exposure, vaccinations can prevent the illness from developing.

No one else has shown symptoms since the bartender’s diagnosis, said state public health director Dr. Jose Montero, and the chances that anyone contracted the disease from the worker are low, given that the person was not directly involved in preparing food.

“But when a place is busy, it’s all hands on deck, and everyone helps,” he said Wednesday.

Public health officials aren’t releasing the name or gender of the bartender, who worked at both the American Legion and the Covered Bridge Restaurant in the Hopkinton village of Contoocook. Anyone who ate or drank at either location between July 20 and Aug. 3 is being asked get vaccinated at clinics being set up Friday from noon to 8 p.m. and Saturday from 9 a.m. to 2 p.m., Montero said.

Officials estimate that the American Legion and the restaurant had 600-1,000 patrons during the time frame in question. Montero said that most children should already be vaccinated against hepatitis A, and that anyone who has been vaccinated in the past does not need to do so again.

The U.S. has seen a dramatic decrease in hepatitis A cases in the last decade, Montero said. New Hampshire had 12 cases in 2008, none in 2011, six last year and three so far this year.

The clinics will be held at Hopkinton High School. The state department of health and human services also will post information on its website: http://www.dhhs.state.nh.us.