Variola minor in Braganca Paulista County, 1956. Flow of the epidemic through the schools of the county.
The characteristics of the 10 elementary, teachers, business and high schools operated in the city capital of the Braganca Paulista County, state of São Paulo, Brazil, during the 1956 epidemic of variola minor (alastrim) are presented. Also shown are the numbers of students with variola and of students without variola but with homemates with variola, by grade and school. Of the total 131 cases recorded among students, 128 occurred in the 4 elementary schools. Of the latter cases, 101 occurred among the students of the JG School and the JT School. The distribution of these cases by age, sex, previous immunity status, school grade and clinical severity of the disease (typed according to Dixon's classification) were remarkably similar in these two schools. Only the ratio of students introducing the disease into their households to students having secondary cases in their households suggestively varied, the JT School having more introductory cases. No student with a previous attack of variola showed any clinical manifestation in any school. Only 2 of the total 101 cases from the JG and JT Schools occurred among students with a previous successful vaccination. Moreover, those two cases apparently resulted from within-household contacts rather than from contacts at the school. No student with current variola showed a severe type (Dixon's types 1 to 5). More than half of the cases typed showed the typical, medium-severity type (Dixon's type 6). More than 2/3 of the cases occurred among students aged 6 to 9 years, particularly among those 7- to 9-year old. The number of cases reached a maximum in the first grade and gradually and definitely decreased with increasing grade.
D000293:Adolescent; D000367:Age Factors; D001938:Brazil; D002648:Child; D004196:Disease Outbreaks / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D012899:Smallpox / Q000453:epidemiology* / Q000635:transmission; D012900:Smallpox Vaccine; D013334:Students; D014611:Vaccination
D012900:Smallpox Vaccine