A total of 800 measles cases across two dozen states have been confirmed, the Centers for Disease Control and Prevention says ...

Tennessee has confirmed its first case of measles for this year amid the outbreak ... and Washington, as shown in the map above. The number of cases this year has already surpassed the number ...

Most vaccinated adults are immune to measles and do not need a booster shot, according to the National Foundation for Infectious Diseases. Editor's note: The map in this story has been updated.