By authors including Jeffrey Gunzenhauser, MD, MPH, Interim Health Officer and Medical Director
and Franklin D. Pratt, MD, MPHTM, Immunization Program, Los Angeles County Department of Public Health
Since measles was eliminated from the United States in 2000, efforts to control reintroduction outbreaks have faced a variety of challenges. An outbreak in California was largely isolated to Los Angeles County and primarily affected a single social group in which anti-vaccination beliefs and behaviors prevailed. The outbreak resulted from a single individual who acquired infection from an unknown source, developed rash on Dec. 2, 2016, and subsequently exposed siblings and other contacts. This produced a clear chain of transmission. In total, 24 cases resulted from this outbreak, with 18 occurring in Los Angeles County and six occurring in nearby jurisdictions.