Measles Activity in California 202ā5 ā As of January 18, 2025
As of January 18, 2025, no confirmed measles cases have been reported in California in 2025. These data are provisional and subject to change.
CDPH will update case counts every two weeks. The next update will be on February 4, 2025.ā
Table. Reported Measles Cases by Month of Rash Onset ā California, 2025
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 2014āApril 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 2012-2017 are available in the Vaccine-Preventable Disease Summariesā. Case counts for 2018-2022 are available in the Vaccine-Preventable Disease Annual Report. Four measles cases were confirmed in California in 2023, and 15 were confirmed in 2024.
For information on measles cases and outbreaks nationwide, please see the CDC Measles Cases and Outbreaks.āā