The measles outbreak in Orange County, California has gone from bad to worse. From seven cases barely two weeks ago, the number of individuals who have contracted the highly contagious disease has skyrocketed to 21.

In a meeting Tuesday, health officials discussed ways on how to respond to the measles outbreak, the biggest so far in California. The state only had three measles cases in the past five years but the first quarter of 2014 alone had health officials dealing with 21 measles patients, seven of whom have been hospitalized.

Measles is a viral disease that primarily affects children but can occur in adults as well. It is characterized by fever, rashes and red eyes.  The disease is so infectious those in close contact with an infected person have high risks of contracting measles unless they are immune to the virus.

Health experts blame the outbreak on people not getting vaccinated and urged residents to review their vaccination history. Children are typically immunized against the disease via the measles, mumps, and rubella (MMR) vaccine. Despite vaccination campaigns, however, there are still children in the U.S. who have not received the MMR shots with some parents refusing to get their children immunized. Some, for instance, fear the MMR vaccine causes autism.

"It's very contagious, and what we're trying to do is prevent the exposure and spread," said Health Deputy Agency Director Eric Handle, "The measles virus can cause inflammation in the brain that can appear immediately, or seven years out."

The Health Department has already set up clinics where people can get tested and vaccinated but health officials warned those experiencing symptoms to call up their doctor first to prevent exposing other people to the virus.

"Don't just go into the middle of the hospital to get tested. Talk to your provider on the phone first, who can maybe talk to us, we can make sure you get tested and treated without exposing other people," Orange county Medical Director Matt Zahn said.

The U.S. Centers for Disease Control and Prevention (CDC) warns of the implications of the disease. "Even in previously healthy children, measles can be a serious illness requiring hospitalization," CDC says. "For every 1,000 children who get measles, 1 or 2 will die from it. Measles also can make a pregnant woman have a miscarriage, give birth prematurely, or have a low-birth-weight baby."