Lack of Measles Transmission to Susceptible Contacts from a Health Care Worker with Probable Secondary Vaccine Failure — Maricopa County, Arizona, 2015

On January 23, 2015, the Maricopa County Department of Public Health (MCDPH) was notified of a suspected measles case in a nurse, a woman aged 48 years. On January 11, the nurse had contact with a patient with laboratory-confirmed measles associated with the Disneyland theme park-related outbreak in California. On January 21, she developed a fever (103°F [39.4°C]), on January 23 she experienced cough and coryza, and on January 24, she developed a rash. The patient was instructed to isolate herself at home. On January 26, serum, a nasopharyngeal swab, and a urine specimen were collected. The following day, measles infection was diagnosed by real time reverse transcription polymerase chain reaction testing of the nasopharyngeal swab and urine specimen and by detection of measles-specific immunoglobulin (Ig)M and IgG in serum by enzyme-linked immunosorbent assay. Because of her symptoms and laboratory results, the patient was considered to be infectious.