Measles spreads primarily through the air when an infected person breathes, coughs, sneezes, or talks, releasing virus-containing droplets into the environment

. These airborne droplets can remain infectious in the air or on surfaces for up to two hours after the infected person has left the area

. People can become infected by breathing in these contaminated droplets or by touching surfaces with the virus and then touching their eyes, nose, or mouth

. An infected person is contagious from about four days before the measles rash appears until four days after the rash develops

. Measles is extremely contagious; if one person has it, up to 90% of nearby unvaccinated individuals will also become infected

. In summary, measles spreads via:

• Airborne droplets from coughing, sneezing, breathing, or talking by an infected person
• Contact with contaminated surfaces followed by touching the face
• Close proximity to infected individuals during their contagious period (4 days before to 4 days after rash onset)

Because of its high contagiousness and ability to linger in the environment, measles can spread rapidly, especially among people who are not immune