The measles virus continues to spread in Orange County, Calif., and so do the efforts to stop it. On Tuesday, 23 unvaccinated high school students were told to go home and stay there until Jan. 29, because another student had been diagnosed with measles and the school does not want it to spread. Measles is highly contagious and simply being in the same room can lead to becoming infected, said Matt Zahn, medical director of epidemiology at the Orange County Health Care Agency.

In California, students are required by law to be vaccinated against childhood diseases. The same vaccine covers measles, rubella and mumps. An exemption to the vaccine can be obtained if the parents sign a waiver because of personal beliefs.

The measles virus is spreading to other counties, too. The current outbreak started when a 20-year old woman became sick while visiting Disneyland and the Disney California Adventure Park in Anaheim. Others became sick rather quickly and the disease spread to other states, including Utah, Colorado, Washington and even Mexico, although the main outbreak is in Orange County.

On Tuesday it was revealed that the measles is now affecting the workers at Disneyland with five workers becoming ill. Disney has since confirmed that three out of the five employees have been treated and have received clearance.

Two of the Disney workers had been vaccinated, and results are still pending on the other three, who have not yet provided proof of their vaccination. Dr. Pamela Hymel, who is the chief medical officer for Walt Disney Parks and Resorts, stated that Disney has been offering immunity tests and vaccinations to all of its employees since they became aware of the outbreak on January 7.

All Disney employees who came into contact with their infected coworkers have been asked to take a paid leave until it is confirmed that they do not have the virus. Each one of the exposed workers will have to either prove that they have been vaccinated, or be willing to take a blood test before returning to work. It has not been revealed how many employees this will affect.

The measles virus has also led to the temporary closing of two medical clinics in San Diego. At the Sharp Rees-Stealy Urgent Care clinic, a patient walked in who was suspected of having the measles virus. Everyone present at the time, including staff, patients and families, were asked about their vaccination history before being allowed to leave. They were also asked to provide contact information. The clinic will be closed until Monday, allowing it to be properly cleaned.

The latest person to become infected with measles is a 22-month-old girl from Mexico. Her family had visited the Disney theme park on Dec. 16 to 18. She had not received the vaccination.

So far, people who became infected with the measles virus at Disney can be found in five states and Mexico. The states include California, Utah, Washington, Oregon, and Colorado.

Measles symptoms can be expected within three weeks after exposure has taken place. This means that no new infections will be seen from the initial outbreak at Disneyland, but people can become infected from those who were infected at that time. This is called secondary infections.