For most of this century health officials thought they had measles under control. The development of a vaccine back in 1963 enabled mass immunization and much of the western world was declared measles-free. But in 2019 the disease made a big comeback in much of the world, including Canada. Measles is a highly contagious infectious disease that is spread through a virus. World Health Organisation officials say its comeback here can be attributed to vaccine-hesitancy.