title: Group A meningococcal disease in the U.S. Pacific Northwest: epidemiology, clinical features, and effect of a vaccination control program.
abstract: In 1975 an outbreak of group A meningococcal disease began in Seattle, Washington, and cases subsequently were recognized throughout the Pacific Northwest. Nearly one-half of the affected persons were Native Americans; two-thirds were alcohol abusers and/or habitués of skid road communities. In Seattle, group A meningococci colonized asymptomatic persons only if these individuals had contact with skid road (P = .006). The epidemic strain may have spread from American Indians in Manitoba, Canada. Traditional migration routes connect the two populations; asymptomatic American Indians on reservations in Washington carried group A meningococci. Vaccination programs were undertaken in four cities but only after cases occurred. In Seattle, vaccination reached 80% of the target population and was associated with a significant decrease in incidence of the disease, but cases recurred after the program ended. The social habits of skid road communities, combined with the "case-triggering" approach to, and premature termination of, vaccination programs, may have resulted in 56% of regional cases occurring after the start of the vaccination program in Seattle.
mesh_terms: D000328:Adult; D001428:Bacterial Vaccines; D002648:Child; D004196:Disease Outbreaks / Q000453:epidemiology*; D005069:Evaluation Studies as Topic; D005260:Female; D006703:Ill-Housed Persons; D006801:Humans; D007198:Indians, North American; D008297:Male; D008350:Manitoba / Q000208:ethnology; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D009345:Neisseria meningitidis / Q000276:immunology*; D009922:Oregon; D014171:Transients and Migrants; D014861:Washington
chemical_list: D001428:Bacterial Vaccines