Measles Situation Update and Revised Clinical Guidance

Health Update -  May 24, 2019

The Los Angeles County (LAC) Department of Public Health (DPH) has confirmed 8 cases of measles in 2019 to date and has investigated thousands of exposures in both adults and children related to these cases. 

Four of the cases were linked to a single case who had traveled internationally and the other 3 cases were unlinked and in residents who had recently returned from travel outside the United States. The majority of cases were unvaccinated, and the remainder were only partially vaccinated. 

While the immediate threat of measles from local cases is waning (the surveillance of exposed contacts ends May 27, 2019), the possibility of new measles cases persists due to global outbreaks. 

There are widespread outbreaks of measles in the U.S. and internationally. The Centers for Disease Control and Prevention (CDC) reported that this year, as of May 20, 2019, there have already been 880 confirmed cases of measles in 24 states, more than any year since measles was declared eliminated from the U.S. in 2000. Outbreaks within the U.S. have been linked to travelers returning from countries or domestic locations with measles outbreaks. 

Assuring immunity across LA County is critical to curb the spread of measles. Clinicians are asked to follow the action steps outlined in the April 26 LAHAN, "Measles Prevention in LA County", including immunizing all international travelers age 6 months or older for whom there is no documentation of immunity to measles and making sure that all (child and adult) patients are up-to-date with their MMR vaccine. 

This notification is to provide updated guidance to clinicians when evaluating a patient for possible measles and includes key provider actions, measles clinical presentation, specimen collection and testing, and common scenarios. Providers are encouraged to view and follow the recently updated DPH Checklist for Measles for Clinicians for step-by-step guidance, as well as the updated Measles Fact Sheet for Clinicians, both found in our Measles Toolkit


Key Messages

  • There have been no new measles cases in the county since May 2, 2019, but the threat of measles persists, primarily due to importation from travel.
  • Based on the current local situation, we have refined our guidance to provide more information on how to evaluate a patient with a febrile rash illness for possible measles based on clinical presentation and risk factors.
  • Providers should continue to assure that their patients are up-to-date with their measles-mumps-rubella (MMR) immunization, should immunize all international travelers age 6 months or older for whom there is no documentation of immunity, and should immediately report suspect measles to Public Health. 

Actions Requested of Providers

  • Immediately isolate patients with an acute febrile rash and institute airborne precautions to prevent possible healthcare-associated exposures.
  • Assess if the patient has measles-like symptoms. A suspect measles case will have both a fever and rash. Presentations may vary based on vaccination status and immunocompetence, but all cases should have both a fever and a rash. 
  • Ask about exposure risk-factors for measles. In L.A. County and California, there are certain epidemiologic risk factors that significantly increase the probability that a patient with an acute febrile rash has measles. Determine if the patient had in the past 4 weeks:

--contact with a known measles case
--contact with an international visitor who was ill 
--traveled outside the U.S., Canada, or Mexico
--traveled through an international airport (even if they traveled domestically)
--lived in or visited a U.S. community where there is an outbreak

See CDC's Global Measles Outbreaks to learn more about locations of domestic and international measles outbreaks.

  • Review measles immunization status and/or serology. Patients with 2 documented MMR doses administered in the U.S. at > 12 months of age are probably immune to measles. Immunocompetent patients with a documented positive IgG are usually considered immune to measles.
  • Report by phone immediately all patients with rash and fever plus an exposure risk-factor for measles, regardless of immunization history. DPH will work with the reporting clinician to determine the likelihood of measles, review any specimen collection recommendations, ensure appropriate isolation precautions are in place for four days after rash onset, and determine if any additional disease control actions are warranted. Note: patients without both fever and rash and without an exposure risk-factor for measles are unlikely to have measles.


Please visit LAHAN for the full version of this health update, which includes information on measles clinical presentation, measles specimen collection and testing, common scenarios and additional resources.



Los Angeles County DPH Morbidity Central Reporting Unit:


Long Beach Health and Human Services:


Pasadena Public Health Department: