Just as California's record-setting flu season seems to be fading, with 278 deaths confirmed as of Friday, health officials warned that another infectious and sometimes deadly virus has arrived -- measles.
Fifteen Californians have come down with measles thus far this year, officials said. And nearly half had opted against childhood vaccination against the disease through the state's personal beliefs exemption.
"Unfortunately, we're off to a bad year in 2014," said state epidemiologist Dr. Gil Chavez, during a phone call with reporters. At the same time last year, there had been only two measles cases, he added.
The California Department of Public Health reported illnesses in six counties: five in Los Angeles County, three each in Orange and Riverside Counties, and four combined in the Bay Area's Alameda, Contra Costa and San Mateo counties. None of the cases have been fatal, but measles can be deadly -- and health authorities remain concerned that many more may have been exposed to the virus.
For every measles case, Chavez said, there may be dozens of people local health officials must track to assure the disease hasn't spread. Earlier this week, fears emerged that thousands of people might have been exposed to measles when a sick UC Berkeley student traveled on the Bay Area Rapid Transit system.
"There's a tremendous burden to the counties and society," Chavez said.
According to the U.S. Centers for Disease Control and Prevention, measles was eliminated in the U.S. in 2000 -- meaning that it no longer circulated here year-round. But people here can still contract the virus when traveling to locations where it is common (including some countries in Europe, Asia, the Pacific, and Africa) or after coming in contact with travelers or others who are infected.
Three of the 2014 measles patients had recently been in the Philippines, where a large outbreak is ongoing; two more had recently traveled to India. Two others had recent contact with travelers.
While two of the measles sufferers had been vaccinated -- the immunization confers protection 99% of the time -- most had not, officials said. Seven had skipped childhood immunizations because their parents opted them out through California's personal belief exemption law. Two doses of measles vaccine are required for students entering kindergarten in California.
Fewer than 3% of California schoolchildren use the exemption, said Dr. Kathleen Harriman, of the public health department's immunization branch.
Chavez said he was particularly concerned about the patients who had intentionally avoided vaccines.
"A myth persists among many parents that the measles vaccine is dangerous," he said. "These illnesses continue to make a comeback because we have people who refuse to be vaccinated."
No one has died of measles in California this year, but the illness can be deadly in cases with complications, officials said. The public health department urged people who have not had measles or received two doses of the measles vaccine to get immunized before traveling outside of the Americas, where the disease is under control.
People who are unsure of their vaccination status should also get immunized before travel, Chavez said.
Also on Friday, the public health department updated its current flu death count to 278, adding 35 new cases since the previous week.
Week by week, the numbers of doctor visits and hospitalizations for flu, as well as deaths, are declining, Chavez said. But he warned that "we're never out of the woods."
"Things seem to be going favorably, but we know flu is unpredictable," he said.