Dr. Ron Chapman, director of the California Department of Public Health (CDPH) and state health officer, announced today that local public health officials have confirmed a total of 59 cases of measles in California residents since the end of December 2014.

Public domain image/National Atlas of the United States
Public domain image/National Atlas of the United States

“If you have symptoms, and believe you may have been exposed, please contact your health care provider. Unless you have an emergency, it is best to contact your health care provider by phone to prevent spread in doctor’s offices.” said Chapman. “The best way to prevent measles and its spread is to get vaccinated.”

Of the confirmed cases, 42 have been linked to an initial exposure in December at Disneyland or Disney California Adventure Park in Anaheim, California. The confirmed cases include five Disney employees. In addition, other cases have visited Disney parks while infectious in January. CDPH recommends that any patient with a measles compatible illness who has recently visited venues where international travelers congregate, such as theme parks, airports, etc., be considered to have a plausible exposure to measles.

Measles is a highly infectious, airborne disease that typically begins with fever, cough, runny nose and red eyes, and within a few days a red rash appears, usually first on the face and then spreading downward to the rest of the body.

Vaccination is the most important strategy to prevent measles. Two doses of measles-containing vaccine (MMR vaccine) are more than 99 percent effective in preventing measles. Measles vaccines have been available in the United States since 1963, and two doses have been recommended since 1989. If you are unsure of your vaccination status, check with your doctor to have a test to check for measles immunity or to receive vaccination.

Local health departments and CDPH continue to investigate reported cases. Several “secondary” cases in persons exposed to the initial group have been reported.  Secondary cases are common with measles. As with the first group of cases, there is a risk of additional transmission in places where the secondary cases have been while infectious. Persons can be infectious for a few days prior to developing symptoms of measles and may feel well enough to be out and about potentially exposing others.

In addition, public health officials are continuing to contact persons exposed to measles cases to determine their vaccination history and implement strategies to prevent spread. This is an ongoing situation, and CDPH expects to receive additional reports of cases.

Measles has been eliminated in the United States since 2000. However, large measles outbreaks have occurred in many countries, particularly in Western Europe, Pakistan, Vietnam and the Philippines in recent years. Travelers to areas where measles circulates can bring measles back to the U.S., resulting in limited domestic transmission of measles. California has many international attractions and visitors come from many parts of the world. It is important for health care providers and the public to be aware that measles transmission can occur in California, and they can prevent transmission by receiving the MMR vaccine.

The California measles patients reside in 11 local health jurisdictions (Alameda, Los Angeles, Orange, Riverside, San Bernardino, San Diego, San Mateo, Santa Clara and Ventura Counties and the cities of Long Beach and Pasadena). Patients range in age from seven months to 70 years. Vaccination status is documented for 34 of the 59 cases. Of these 34, 28 were unvaccinated, one had received one dose and five had received two or more doses of MMR vaccine.

Health care providers treating patients with fever and a rash should consider measles, and ask patients about travel to international destinations and domestic venues that are popular with international visitors. People who are unvaccinated should know that there is presently a risk for acquiring measles in California.