Residents in high-income countries around the world, where more parents are hesitating to vaccinate their kids, (including England, France, and Japan) have started to witness just how virulent the measles can be. The measles is said to be so contagious that 90% of people exposed to the virus (who are not vaccinated or immune from a previous illness) will get it. Image courtesy CDC/Smith Collection/Gado/Getty Images A US schoolboy receives his measles vaccination during field trials to determine the vaccine's effectiveness in 1962 at Fernbank School in Atlanta, Georgia.
