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IMMUNIZATION BRANCH

Measles

​Measles is a highly contagious viral disease. It is widespread in many parts of the world, including Europe, Africa, and Asia. Measles begins with a fever that lasts for a couple of days, followed by a cough, runny nose, conjunctivitis (pink eye), and a rash. The rash typically appears first on the face, along the hairline, and behind the ears and then affects the rest of the body. Infected people are usually contagious from about 4 days before their rash starts to 4 days afterwards.
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Measles Activity in California - As of August 21, 2019

The last large outbreak of measles in California was associated with Disneyland and occurred from December 2014-April 2015, when at least 131 California residents were infected with measles; the outbreak also infected residents of six other states, Mexico, and Canada.

In 2019, five outbreaks have been reported in California; four of the outbreaks were linked to patients with international travel, while one had an unknown source.

As of August 21, 2019, 66 confirmed measles cases, including 38 outbreak-associated cases (4 completed outbreaks, 33 cases; 1 ongoing outbreak, 5 cases), have been reported.

CDPH will update case counts weekly on Thursdays if new cases are reported.

Table 1. Total Reported Measles Cases in California, 2019

CountyTotal CasesPediatric Cases (<18 Years)Adult Cases (18 Years or Older)
​Alameda*​1​0​1
​Los Angeles*18​3​15
​Orange4​1​3
​Placer​3​2​1
​Sacramento​3​2​1
​San Bernardino​2​1​1
​San Diego​2
​1​1
​San Francisco​1​0​1
​San Mateo5​1​4
​Santa Barbara​2​02
​Santa Clara5​14
​Santa Cruz1​0​1

​Other§

19​316
​Total66
1551
*Alameda County includes two health departments that report cases separately: Alameda County and Berkeley City. Los Angeles County includes three health departments that report cases separately: Los Angeles County, Pasadena City, and Long Beach City.
The rash onset for one of these patients occurred in late December of 2018. Due to reporting methods of the Centers for Disease Control and Prevention, the patient will be included in California's 2019 case counts. 
 §To address potential confidentiality concerns with small numbers, data from counties with populations less than 250,000 are not individually displayed.

Table 2: Measles Outbreak-Associated Cases--California, 2019

Outbreak

Total Cases
​Los Angeles Region Outbreak II​5
​Northern California Outbreak (ended)21
​Los Angeles Region Outbreak (ended)​5
​Sacramento Region Outbreak (ended)​4
​San Francisco Bay Area Outbreak (ended)​3
​Total​38

Table 3. Reported Measles Cases by Week of Rash Onset - California, 2019

​Week Ending Date​Total Cases
​1/5/2019​2
​1/12/2019​0
​1/19/2019​0
​1/26/2019​0
​2/2/2019​0
​2/9/2019​0
​2/16/2019​1
​2/23/2019​1
​3/2/2019​2
​3/9/2019​1
​3/16/2019​0
​3/23/2019​8
​3/30/2019​3
​4/6/2019​4
​4/13/2019​4
​4/20/2019​8
​4/27/2019​5
​5/4/2019​4
​5/11/2019​1
​5/18/2019 2
​5/25/2019​0
​6/1/2019​4
​6/8/2019​2
​6/15/2019​3
​6/22/2019​0
​6/29/2019​2
​7/6/2019​1
​7/13/2019​2
​7/20/2019​1
7/27/2019​2
​8/3/2019
​0
​8/10/2019
​1
​8/17/2019
​0
​8/24/2019
​1

Rash onset date is unknown for one patient.

Table 4: Known vs. Unknown Vaccination History of Reported Measles Cases-California 2019‡

Vaccination Status​Number Percent
​Known Vaccination Status​43​69%
​Unknown Vaccination Status​19​31%
​Total​62​100%

‡ Table last updated on July 24, 2019; table updated when 5 or more new cases have occurred, to preserve confidentiality.

Table 5. Number of Documented Doses among Pediatric (<18 years old) Measles Cases with Known Vaccination Status -- California, 2019‡

​Vaccination Status

​Number

​Percent

​Unvaccinated​12​100%
​Total​12​100%

‡ Table last updated on July 3, 2019; table updated when 5 or more new pediatric cases have occurred, to preserve confidentiality.

Table 6. Number of Documented Doses among Adult (≥18 years old) Measles Cases with Known Vaccination Status -- California, 2019‡

Vaccination Status​Number​Percent
​Unvaccinated​13​48%
​Vaccinated, 2 or more doses​12​44%
​Vaccinated 1 dose​2​7%
​Total​27​100%

‡ Table last updated on July 3, 2019; table updated when 5 or more new adult cases have occurred, to preserve confidentiality.

For more information on why some vaccinated people develop measles, please see this CDPH Measles FAQ (PDF).

Case counts for 2012-2017 are available in the Vaccine-Preventable Disease Summaries.  As of April 24, 2019, 22 confirmed measles cases were reported in California in 2018; these data are provisional and subject to change.

For information on measles cases and outbreaks nationwide, please see the CDC Measles Cases and Outbreaks.

 

If you are having difficulty accessing documents on this page please call  510-620-3737 or email ImmunizationBranch@cdph.ca.gov to request this information in an alternate format.

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