In Reply Measles was eliminated from the United States in 2000 almost entirely due to routine childhood immunizations. The reemergence of measles and other vaccine-preventable diseases is a direct consequence of parents delaying or refusing to have their children vaccinated.
It is always difficult to identify the causes of particular outbreaks, but it strains credulity to suggest that unvaccinated children did not play a part in the spread of measles infection originating in Disneyland.
Gostin LO. Exemptions to Vaccination for Children—Reply. JAMA. 2015;314(3):299-300. doi:10.1001/jama.2015.6615