South Carolina health officials confirmed the number of mumps cases at the College of Charleston has reached 21.
This comes after an outbreak of the virus was reported in September when three cases of the virus were confirmed by the S.C. Department of Health and Environmental Control.
In response to the outbreak, the college advised students to get two doses of the measles, mumps and rubella (MMR) vaccine. They have also organized pop-up clinics where students could get vaccinated on campus.
The mumps is a viral infection that is spread through infected saliva, including from coughs, sneezes and shared utensils. Some of the symptoms are fever, headache, muscle ache and swollen salivary glands.
According to DHEC, one dose of the MMR vaccine has been found to be 78 percent effective in preventing the virus. Two doses is nearly 90 percent effective.
While cases of the mumps have declined nationally over the decades, the Mayo Clinic reports, outbreaks still often occur in close-contact spaces like colleges and schools, and where people are not vaccinated.
To be a student at the college, an applicant can either turn in health records indicating they have been vaccinated or a waiver stating they are declining to get vaccinated. When the outbreak was originally announced more than a month ago, nearly 200 students out of almost 12,000 student medical files had turned in a vaccine waiver.
The first three confirmed cases of the virus at the school involved both vaccinated and unvaccinated students.