Endemic means a disease that occurs at a predictable rate in a certain place or group of people. For example, chickenpox occurs at a high and predictable rate among American schoolchildren.
Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.