A measles outbreak in Orange County is the worst in California so far this year, and officials expect the fever and rash-inducing disease to continue to spread.
The county outbreak has reached a state high 21 cases in 2014, five of which have involved children, according to a news release from the Orange County Health Care Agency on Wednesday.
Health officials urged residents to get vaccinated to prevent from the disease, noting that the children who contracted measles had not been immunized.
"There are pockets of activity in Orange County where parents believe that immunizations are not important nor necessary," said Dr. Eric Handler, director of the Orange County Health Care Agency.
The disease likely made its way to Orange County by a traveler, officials said.
"Anyone that comes to the hospital with symptoms that we are concerned that have measles, we put them in what's called a negative air flow room that basically just sucks the viruses out of the air, and everyone goes in with a mask," said Dr. Greg Young, emergency room physician.
Measles is highly infectious and particularly detrimental to people with underlying health conditions and the very young.
Resident Sylvester Reyes made sure his granddaughter got vaccinated.
"I think it's important with the measles," Reyes said. "Right here in Orange County, they've got a problem with the measles."
The outbreak comes not long after an unusually severe flu season settled down. More than 270 Californians had died from flu-related illnesses as of February 21.
"It was awful. It just seemed to last forever, and the rash was everywhere," said hospital employee Jennifer Quintero, who had the measles when she was 5 years old. "Just not a fun time."
Officials in New York City Tuesday said an outbreak there has grown to 20 cases.