After an on-campus student was diagnosed with chickenpox, the Center for Health and Wellness asked people who are susceptible to the disease to get a vaccination or leave campus by today, according to Jane Powers, the director for health and wellness. 

The warning is for students who have never been vaccinated against, or never been sick with chickenpox, Powers said. 

A letter sent to students who do not have any record of having a chickenpox vaccination said the notice was to avoid the spread of the illness to the greatest possible extent. 

They were asked to leave campus until the risk of exposure is gone, from Nov. 8 to 20, Powers said. 

“It’s the unvaccinated people that are most at risk,” Powers said in an interview. “Those truly at highest risk are nonimmune students who have a significant health condition.”

According to Powers, the center has administered 41 vaccinations since Friday, and Boston’s Department of Public Health is sending 30 more doses.

There are eight students in the infected student’s residence hall who still need to provide documentation to show if they have been vaccinated, according to Powers. She said the college needs to report the documentation to the Department of Public Health by Friday. An additional 22 students who live in other residence halls, and 20 other students who live off-campus, must provide their documentation by Nov. 16, Powers said.

Powers said four cases of chickenpox have appeared on campus in the past 16 years. 

According to the letter, students can get vaccinated at Emerson’s wellness center, The Fenway Community Health Center, or Boston University Affiliated Physicans. 

Powers said only one student was diagnosed with the disease and was immediately sent off campus. No students have come forward with a new case yet, she said, although the incubation period is now ending. This means that if people were to get sick, they would start showing symptoms in the next few days.

“It doesn’t happen very often,” Powers said. 

Chickenpox, or varicella, is a highly contagious virus that causes an itchy rash resembling blisters, according to the Massachusetts Department of Health’s website, and most commonly affects people under the age of 15. 

According to an email advising the Emerson community about the presence of the virus on campus, students who were at the dining hall, The Max Mutchnick Cafe, or Emerson’s Cafe between Oct. 29 and Oct. 31 may have been exposed. 

Billy Boorn, a freshman visual and media arts major, said he received the letter about the risk because his health records did not show he ever had chickenpox or received the vaccination. When he said he already received the vaccination, he had to take a blood test to prove his immunity.

“It’s an inconvenience, but it was my fault for forgetting to turn in my records,” Boorn said. “It’s annoying, but I don’t feel wronged in anyway.”

Boorn said the Center for Health and Wellness also warned him via email and placed a hold on his student account. 

Jasminne Young, a sophomore journalism major, said she is against removing non-vaccinated students from campus. 

“I think that this is a good safety precaution, but I think the school could be handling it differently,” Young said. 

Abagael McCauley, a sophomore marketing and political communication double major, said she agreed.

“I can understand why the college wants to protect the students,” she said. “But I think there are other ways to solve this problem instead of asking students to leave the campus.”

Ryan Catalani and Tyler Deffebach contributed reporting to this article.