(Undated) -- Mumps is making its rounds across the state this year and many of the people who've fallen ill are adults. Dr. Vidya Sundareshen, with the SIU School of Medicine, explains what these people are experiencing. Part of the reason why the adults are getting infected is because they haven't had two doses of the mumps vaccination. People who have the mumps should stay home until five days after their swelling has gone down. There are ways to prevent the spread of mumps. They include washing hands frequently and cleaning surfaces that an infected person has touched.