An Outbreak of Varicella among children attending preschool and elementary school in Illinois.
In our investigation of a varicella outbreak among students in preschool, kindergarten, and grades 1-3 in Winnebago County, Illinois, we found an overall varicella vaccine efficacy of 88%, evidence that the circulating virus was a wild-type strain (as determined by polymerase chain reaction analysis), and evidence that vaccination of children </=15 months of age was associated with an increased risk for breakthrough varicella (relative risk, 3.7; 95% confidence interval, 1.1-13.1; P=.04). The efficacy of varicella vaccine might be improved if administration of the initial vaccine dose is delayed until children are >/=15 months of age.
Dworkin
Mark S
MS
Division of Infectious Diseases, Illinois Department of Public Health, Springfield, IL, USA. mdworkin@idph.state.il.us
Jennings
Charles E
CE
Roth-Thomas
Jayne
J
Lang
Jo Ellen
JE
Stukenberg
Carol
C
Lumpkin
John R
JR
D002644:Chickenpox / Q000453:epidemiology* / Q000517:prevention & control; D019433:Chickenpox Vaccine / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000517:prevention & control; D004196:Disease Outbreaks; D006801:Humans; D007087:Illinois / Q000453:epidemiology
D019433:Chickenpox Vaccine