A-list celebs Madonna, Gwyneth Paltrow, Demi Moore, Ashton Kutcher and others have been warned that they are at risk for Hepatitis A following Kutcher’s 30th birthday party at the New York City nightclub Socialista. The New York City Department of Health has warned the stars that they — and anyone else who made a visit to Socialista on three nights in early February — should get a Hepatitis A vaccine as a precaution.

According to the New York City Department of Health, a bartender who worked at the West Village nightclub on February 7, February 8 and February 11 has tested positive for Hepatitis A. Kutcher’s birthday party was held at Socialist on February 7. A health department official told The New York Times that as many as 1,000 other people might have been at Socialista on those nights. The restaurant has turned over lists of names from 30 to 40 reservations made on those nights, but the department has not gone through credit card receipts.

Hepatitis A is a contagious liver infection. The virus is found in the stool of infected people, and can be spread if they do not wash their hands thoroughly after using the bathroom. Symptoms of Hepatitis A include low-grade fever, nausea, vomiting, diarrhea, rash, yellowing of the skin, dark brown urine, loss of appetite and fatigue. Symptoms of Hepatitis A can last from two to nine months. Once someone has been infected with Hepatitis A, there is no real treatment. Usually, bed rest is prescribed, and efforts are made to make the patient’s symptoms more tolerable until the disease runs its course. In some instances, a patient will be hospitalized to treat dehydration or liver problems. Sometimes patients with a severe case of Hepatitis A will require a liver transplant.

Outbreaks of Hepatitis A have been linked to popular restaurants in the past. The largest Hepatitis A outbreak in US history occurred in Pennsylvania in 2005. More than 500 people contracted Hepatitis A, and three died after eating at a Chi-Chi’s Mexican Restaurant. That outbreak was linked to tainted green onions.

Health officials said yesterday the department had learned of the case on Tuesday and on Wednesday had sent an inspector to Socialista, at 505 West Street, between Jane and Horatio Streets. According to the New York Times, the health department issued what it called a “precautionary notification” after the inspector reported that no soap was available for hand washing at the restaurant.

Immune globulin (IG), a preparation of antibodies can prevent Hepatitis A if it is administered within two weeks of exposure. The New York City Health Department is offering Hepatitis A vaccines to Socialista attendees. The department will give the vaccinations at Public School 41, at 116 West 11th Street on Friday from 4 p.m. to 10 p.m., on Saturday from 1 p.m. to 8 p.m. and on Sunday from 1 p.m. to 6 p.m.