This seems to be the message the New York City Health Department is transmitting to all celebrities attending Ashton Kutcher’s 30th birthday at New York City hot spot Socialista Bar, Reuters reports.

Moreover, the city health officials issued a statement, warning anyone who visited Socialista on February 7, 8 and 11 to get a vaccination.

"Any patron who visited the establishment after 8 p.m. on February 7th or 8th, or after 10 p.m. on February 11th is considered to be at risk and needs a preventive shot," the Health Department said.

The warning comes after a bartender working there has been diagnosed with the disease. Now, city health officials say he might have passed hepatitis A to club patrons early this month. The bartender only worked on three nights (February 7, 8 and 11) when he might have been infectious, but one of those nights – February 7 – was the night of Kutcher’s birthday party. Demi Moore, Madonna, Gwyneth Paltrow, Molly Sims, Eric Dane, Lucy Liu, Kate Hudson, Liv Tyler, Salma Hayek, and Bruce Willis were all exposed to the risk of getting the hepatitis virus that day as well.

There was no immediate comment from reps for Kutcher or Demi Moore, who threw the party for her life partner.

According to the Health Department, an estimated 700-800 people may have visited Socialista the nights the infected bartender worked. The good news is that no additional cases of illness have been identified.

However, the Health Departemnet will be offering free vaccination at P.S. 41 elementary school at 116 West 11th St. near 6th Avenue in Manhattan to patrons at the following times: Friday, Feb. 22, 4 p.m. – 10 p.m.; Saturday, Feb. 23, 1 p.m. – 8 p.m.; Sunday, Feb. 24, 1 p.m. – 6 p.m.

“We are asking these bar patrons to get this vaccination as a precautionary measure,” said Dr. Sharon Balter, Medical Epidemiologist at the Health Department. “If people experience symptoms, they should see a doctor, but for most people bed rest and avoiding alcohol are all that is needed to recover. This incident serves as an important reminder to always wash [your] hands thoroughly and regularly to prevent the spread of disease.”

Hepatitis A is a liver disease caused by a virus, which is spread from person to person by putting something in the mouth that has been contaminated with traces of fecal matter from an infected person, the department said. The disease is rarely fatal and symptoms include jaundice, fatigue, abdominal pain, nausea, and diarrhea. Most people recover within a few weeks.