Overview Measles is a highly contagious, serious viral disease. Before the introduction of measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every two to three years and caused an estimated 2.6 million deaths each year. An estimated 128 000 people died from measles in 2021 – mostly children under the age of five years, despite the availability of a safe and cost-effective vaccine. Measles is caused by a virus in the paramyxovirus family, and is normally passed through direct contact and the air. The virus infects the respiratory tract, then spreads throughout the body, causing severe disease, complications and even death.