Measles Prevention in Los Angeles County

Health Update -  April 26, 2019

The count of confirmed measles cases in Los Angeles County remains at 5. An additional 5 cases were diagnosed among travelers who do not reside in Los Angeles County. The Los Angeles County (LAC) Department of Public Health (DPH) is conducting outreach to identify and conduct contact investigations for hundreds of exposures.

The April 22 health alert summarizes immediate steps to take when evaluating a person with possible measles. This communication is to outline recommendations to protect patients, staff, and the community from measles.

During this outbreak where there may be more measles virus in circulation, DPH is encouraging providers to review vaccination status with all children and adults during routine patient visits and to immunize patients who are unvaccinated or undervaccinated. Note: there is currently no shortage of measles vaccine.


Key Messages

  • LAC DPH is currently investigating hundreds of measles exposures. Providers are reminded to report all patients with suspect measles immediately to Public Health without waiting for laboratory confirmation (see Reporting below).
  • At routine visits, all healthcare providers should make sure their patients are up-to-date with their measles-mumps-rubella vaccine (MMR), the most effective way to prevent measles and its complications.
  • Healthcare providers should ask patients about planned international travel and vaccinate all travelers age 6 months or older for whom there is no documentation of immunity (see International Travelers below).
  • All healthcare staff should have documented measles immunity.

Actions Requested of Providers

  • Review measles immunization status with all patients at their regular visits. Providers are encouraged to use the California Immunization Registry (CAIR) to review past immunizations and enter doses given. Documentation of measles vaccination includes medical and provider records with dates, and records from government vaccine registries.
  • Vaccinate all patients who do not have documented immunity or who are under-immunized.

Two doses of MMR are recommended for all school aged children (and required for school entry) and for adults at increased risk of measles who include the following:

--Students at post-high school educational institutions including universities

--Staff at schools (pre-kindergarten through post-high school educational institutions) and daycares

--Health care personnel or any person working in a hospital

--International travelers >12 months of age (see International Travelers)

--Household, close personal contacts, or caregivers of immunocompromised persons with no evidence of immunity to measles

--HIV infection with CD4 count ≥200 cells/μL for at least 6 months and no evidence of immunity to measles

--Persons caring for infants or living in households with infants

--Women of childbearing age who are not pregnant but may be planning to get pregnant in the future

One dose of MMR is recommended for children at age 12 months. For infants 6-12 months who travel internationally (see International Travelers).​

At least one dose* of MMR is recommended for all other adults.

*Note: During contact investigations, people with an exposure to measles and documentation of only a single dose of MMR may be subject to exclusion from work or school and/or quarantined. With documentation of two doses of MMR or serologic confirmation of immunity, exclusion and/or quarantine may be avoided. As many adults will not have documentation of immunization, providers are encouraged to discuss the current situation, assess the patient's individual risk of acquiring or transmitting measles, and consider testing for immunity or vaccinating with 1 or 2 doses of MMR as appropriate. There is no harm from administering additional doses of MMR vaccine.

See ACIPs Immunization Schedules for Health Care Professionals for more information on child and adult recommended immunizations.

  • Actively identify unvaccinated and under-vaccinated children in your practice to get them up-to-date with measles immunizations.
  • Actively review immunization records of women who desire pregnancy or may become pregnant to determine the need for vaccination because MMR is contraindicated during pregnancy. Women should be counseled to avoid becoming pregnant for 28 days after administration of MMR vaccine.
  • Ensure that all health care workers are immune to measles. All staff, even those who do not have a direct patient care role, should have 2 documented doses of MMR or serologic demonstration of immunity.
  • Display posters to educate patients and staff about measles and post signs outside entrances to health care facilities. Visit LAC DPH to download.


International Travelers

Healthcare providers should ask patients about planned travel and vaccinate per ACIP guidelines:

  • Infants aged 6 through 11 months of age who will be travelling internationally should receive a dose of MMR before travel, although this dose does not count towards completion of the routine schedule.
  • All children and adults ages 12 months and older should receive 2 doses of MMR vaccine separated by at least 28 days, with the first dose administered at age >12 months. For more information see the International Travelers Aged ≥6 Months section of Prevention of Measles, Rubella, Congenital Rubella Syndrome, and Mumps 2013 MMWR. 


Measles Immunity During Contact Investigations

The following is considered acceptable evidence of immunity against measles after exposure:

  • Documented receipt of two measles-containing vaccines
  • Laboratory evidence of immunity or prior infection

Persons born before 1957, persons with only one documented dose of MMR, and unvaccinated persons, if exposed to measles, will be required to have laboratory evidence of immunity or they may be subject to exclusion or quarantine.

Self-reported vaccination or infection does not constitute evidence of immunity.

To determine if a person is immune to measles without documented proof of receipt of MMR doses, collect serum for measles IgG testing.



Measles cases must be reported by telephone immediately to the local health department (Title 17, California Code of Regulations, § 2500).

Los Angeles County DPH Morbidity Central Reporting Unit:


Long Beach Health and Human Services:


Pasadena Public Health Department: