Measles

Measles Activity in California 202​4 – As of November 9, 2024

As of November 9, 2024, 14 confirmed measles cases have been reported in California. These data are provisional and subject to change.

CDPH will update case counts every two weeks. The next update will be on November 26, 2024

Table. Reported Measles Cases by Month of Rash Onset – California, 2024 ​

Outbreaks

While high levels of immunity in the general population ultimately limit measles outbreaks, measles readily spreads in communities and social networks with lower coverage. 

In December 2014–April 2015, at least 131 California residents were infected in a large measles outbreak associated with Disneyland; the outbreak also infected residents of six other states, Mexico, and Canada.

In 2019, there were 73 confirmed measles cases in California, including 41 cases associated with six outbreaks (defined as 3 or more cases). Of the six outbreaks, five were linked to patients with international travel, while one had an unknown source. The largest outbreak consisted of 21 cases and involved multiple generations of transmission in a health care setting. The other five outbreaks involved from 3 to 5 cases.

Case counts for 2012–2018 are available in the Vaccine-Preventable Disease Summaries. Case counts for 2019–​2021 are available in the Vaccine-Preventable Disease Annual Report. There were no measles cases reported in California in 2022 and 4 measles cases were confirmed in California in 2023.

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.​