Measles Outbreak in San Diego: Lessons Learned

In February 2008, the Immunization Branch assisted the San Diego Health and Human Services Agency in investigating a measles outbreak. An unvaccinated seven year old child with a PBE who had traveled to Switzerland was reported to San Diego County on February 1, 2008 as having measles.

Subsequently, 11 additional measles cases in unvaccinated infants and children aged 10 months to nine years were identified. A more detailed account of the outbreak investigation is available in the MMWR at: www.cdc.gov/mmwr/preview/mmwrhtml/mm5708a3.htm

Experience during this outbreak highlighted a number of issues related to infectious disease control including:

·        Increased risk of vaccine-preventable disease outbreaks in communities with unvaccinated children using California’s personal belief exemption

·        Lack of clinician familiarity with measles symptoms and consideration of measles in patients with febrile rash illness and history of recent international travel

·        Failure to implement appropriate infection control precautions in both ambulatory and acute care settings

·        Delayed diagnoses due to out-of-state laboratory testing

·        Lack of immediate reporting of suspect cases to the local health department.

The Immunization Branch strongly encourages that blood or other clinical specimens for suspected measles cases be sent to the county laboratory. The county laboratory will forward the specimens to the CDPH’s Viral & Rickettsial Disease Laboratory (VDRL), http://www.cdph.ca.gov/programs/vrdl/Pages/default.aspx
rather than to the usual reference laboratory of the clinician or health care facility.

Clinicians suspecting measles in a patient should take the following steps to minimize the risk of transmission in health care settings:

·        Separate the possibly infectious patient from others, applying appropriate isolation practices, including as many elements of airborne precautions as possible, in addition to standard precautions for such patients (see Page 2 of 7 of CDC’s Guideline for Isolation Precautions http://www.cdc.gov/ncidod/dhqp/gl_isolation.html ).

·        Limit the number of individuals exposed to the patient; restrict health care personnel and visitors without documented evidence of immunity from entering the patient’s room.

·        Place patients in isolation— preferably an airborne infection isolation room, as soon as possible; they should not remain in patient waiting areas. Keep the exam room door closed.

·        Do not reuse the examination room for at least two hours after the infectious patient leaves.

·        Do not refer patients to other locations for lab tests—unless infection control measures can be implemented at those locations.

·        Notify the local health department immediately about any suspected measles cases seen in clinical practice.

·        Instruct persons who were exposed to measles to inform all health care providers of their exposure prior to entering a healthcare facility.  Such patients should be seen at the end of the day and should enter through a side door if possible and be placed immediately in an exam room with the door closed.  Such patients should not wait in the waiting room.

·        Ask patients to put on a surgical mask prior to, or immediately upon entering a healthcare facility.