Adverse Events Associated with 17D-Derived Yellow Fever Vaccination

In June 2001, seven cases of yellow fever vaccine--associated viscerotropic disease (YEL-AVD) (previously called multiple organ system failure) in recipients of 17D-derived yellow fever vaccine (YEL) were reported to the Advisory Committee on Immunization Practices (ACIP) (1--3). ACIP reviewed the cases, recommended enhanced surveillance for adverse events, and updated the ACIP statement on YEL (4). This report summarizes the preliminary surveillance findings, including two new suspected cases of YEL-AVD and four suspected cases of YEL-associated neurotropic disease (YEL-AND) (previously called postvaccinal encephalitis). Although YEL remains essential for travelers to areas in which yellow fever (YF) is endemic (Figure), these findings underscore the need for continued enhanced surveillance and timely clinical assessment of YEL-associated disease.