Spread of variola minor in households.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000453:epidemiology; D005006:Ethnicity; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012111:Residence Characteristics; D012572:School Health Services; D012899:Smallpox / Q000453:epidemiology*; D012959:Socioeconomic Factors; D014611:Vaccination