another surge of cases could occur if someone with measles visits the state, given the high number of foreign tourists and people in the state who are not vaccinated.California allows exemptions from vaccinations for medical reasons and "personal beliefs." There were about 1,000 medical exemptions in the state during the 2013-2014 school year, and more than 17,000 philosophical exemptions.Measles is a highly contagious respiratory disease. It causes fever, red and sore eyes, runny nose, cough and a rash. It can cause deadly health complications, including pneumonia and encephalitis. It is spread by contact with an infected person through coughing or sneezing. It can remain in the air and on surfaces for up to two hours.While once widespread in the United States, cases dropped significantly because of vaccines. In 2000, health authorities declared that measles had been eliminated in the United States, which meant it was no longer native but continued to be brought in by international travelers.