Incidence of acute transverse myelitis in Rochester, Minnesota, 1970-1980, and implications with respect to influenza vaccine

Acute transverse myelitis is a clinical entity characterized by acute onset of nonrecurrent, bilateral but not necessarily symmetrical, cross-sectional sensorimotor involvement of the spinal cord. Vascular lesions, inflammatory (mainly viral) disorders, and necrotic myelopathy as a remote effect of cancer have been reported as possible etiologic factors. Epidemiologic data on the disease are scarce. From the Mayo Clinic records-linkage system, 5 cases fulfilling the diagnostic criteria of acute transverse myelitis were collected during the study period 1970–1980 among the residents of Rochester, Minn. (USA), providing a mean annual incidence rate of 0.82 per 100,000 person-years, or 1.2 per 100,000 person-years for those 18 years of age and over. None of the cases described were post-vaccinal; an estimate of the number of cases occurring fortuitously following the swine flu vaccination program of 1976 in the USA is provided.