Kane MS, et al. - Among children 1–18 years, researchers conducted this retrospective cohort study within Kaiser Permanente Northern California population to evaluate acute flaccid myelitis (AFM) [defined as an acute onset of limb weakness with longitudinal spinal gray matter lesions] incidence, risk factors and outcomes in a fixed population. The study criteria for AFM were met by a total of 28 patients. Male sex, Asian ancestry and history of asthma, atopic dermatitis or head injury were included risk factors. There were no risk factors related to poliomyelitis. It was noted that prodromal illness was common. The most common pathogen detected was enterovirus. The findings support previous male sex and atopy reports as risk factors. This study's unique findings were interval increase in incidence, predisposing Asian ancestry and history of head injury. The overall prognosis was better than previous reports, but in several patients recovery was incomplete.