Disneyland officials say five employees have been diagnosed with measles in the last week as the outbreak, which began at the theme park, rose to 53 people.
"As soon as the OC Health Care Agency notified us on January 7, we immediately began to communicate to our Cast to raise awareness," Dr. Pamela Hymel, chief medical officer at Walt Disney Parks and Resorts said in a statement.
"In an abundance of caution, we also offered vaccinations and immunity tests."
The measles outbreak was traced back to people who visited Disneyland between December 17 and 20 but has since spread across California, Washington, Utah, Colorado, and Mexico.
"It’s pretty ubiquitous now throughout the county," said Dr. Eric Handler, Orange County’s public health officer.
"Clearly, we have an unprotected population that needs to be immunized to halt the spread of the disease."
Park officials said three of the affected employees have been treated and cleared.
Other staff who may have come into contact with these employees and had not been vaccinated or cannot confirm they are immune have been put on paid leave, Disneyland officials said.
"Nothing could have been done to prevent this outbreak given that measles is present in many parts of the world, and there are susceptible people in the US. The only way to prevent measles is through immunization, and this outbreak is a reminder that measles is just a plane ride away from the United States," a recent statement by the California Department of Public Health said.
