As the measles outbreak that began at the Disney theme parks last month continues to spread, state health officials say people who are not vaccinated against the highly contagious disease should avoid visiting Disneyland or California Adventure.
"It is positively safe to go to Disneyland if you are vaccinated, because you don't have to worry about whether there have been recent cases or recent transmissions there," California's state epidemiologist Gil Chavez said Wednesday.
"But if you are unvaccinated, I would worry about it," he said.
He added: "If you have a minor that can not be vaccinated, or a child under 12 months of age, I would recommend that those children or infants are not taken to places like Disneyland today."
There are now a total of 67 confirmed cases of measles since the outbreak began last month, according to the California Department of Public Health.
Those infected at the theme parks have passed it to people back in their communities. And as the disease has circulated beyond Disneyland, it has also returned, said Chavez, noting that infectious visitors and employees have visited the theme parks in January.
There are 59 cases in California, including 20 in Orange County, 10 in San Diego County and nine in Los Angeles County.
There are also five cases among Disneyland employees, the most recent of whom developed the telltale rash on January 18, the Department said, adding that there are eight cases outside the state, in Utah, Colorado, Washington, Oregon and Mexico.
Of the 34 cases with known vaccination status, 28 were unvaccinated and one had received one dose of the vaccine, according to the Department. Five had received two or more doses of the MMR vaccine, it added.
The outbreak began when someone infected with measles visited the Anaheim theme parks between December 17 and 20, health officials say. They believe a foreign tourist, or an American who traveled abroad, brought the disease to California.
But, Chavez added, the true source of the outbreak is, "one of those mysteries that we may never solve."
Measles was eliminated from the country in 2000. But last year, 61 California residents contracted the disease. And three weeks into 2015, the state has already seen more cases than all of last year.
Chavez said public health efforts to contain the disease are made harder by the pockets of unvaccinated people, adding: "That really presents a huge challenge when it comes to us having measles circulating in the state as we do now, because of this introduction of measles."
State health officials expect to see more cases, but are confident that they will keep the outbreak under control.