Measles is a very contagious virus that spreads easily from person to person. It spreads through the air when someone with the virus coughs, sneezes, talks, or breathes. The virus can stay in the air or on surfaces for up to 2 hours. If you’re not protected, 9 out of 10 people who are exposed will get sick. People with measles can spread the virus 4 days before the rash appears and up to 4 days after.
