Distribution of Students, Cases, and Disease and Vaccination History by Wing: Arkansas, 2003

VariableWest WingEast WingP
Total number of students270275NA
Median age of students, y (range)9 (5–12)6 (5–8)<.001
Had history of diseasea40%15%<.001
Had history of vaccinationb92%99%<.001
No or unknown disease and vaccination historya,c7%1%.0004
No. of varicella cases444NA
Overall varicella attack rate2%16%<.001
AR among students without disease historyd3%19%<.001
AR by classroom among students without disease history, range0–14%7–41%NA
  • AR indicates attack rate; NA, not applicable.

  • a Before the start of the outbreak.

  • b Had no previous history of disease.

  • c Children who had: (1) no history of disease and no history of vaccination, (2) no history of disease and unknown vaccination history, (3) unknown history of disease and no vaccination history, or (4) unknown history of disease and vaccination.

  • d Four case patients had previous history of disease.