Measles is spread through contact with infected nasal or throat secretions, or by breathing in the virus after it's coughed, sneezed or sent into the air by an infected person, according to WHO. The measles virus can remain contagious in the air or on contaminated surfaces for up to two hours.

Health and Human Services Secretary Robert F. Kennedy Jr. urged the public to get the measles-mumps-rubella vaccine after a second school-aged child died from the virus in Texas, calling it the “most effective” way to prevent the spread of measles.