title: Changing varicella epidemiology in active surveillance sites--United States, 1995-2005.
abstract: Significant reductions in varicella incidence were reported from 1995 to 2000 in the varicella active surveillance sites of Antelope Valley (AV), California, and West Philadelphia (WP), Pennsylvania. We examined incidence rates, median age, and vaccination status of case patients for 1995-2005. Coverage data were from the National Immunization Survey. By 2005, coverage among children 19-35 months of age reached 92% (AV) and 94% (WP); 57% and 64% of case patients in AV and WP, respectively, were vaccinated; and varicella incidence declined by 89.8% in AV and 90.4% in WP. Incidence declined in all age groups, especially among children <10 years of age in both sites and among adolescents 10-14 years of age in WP. In AV, since 2000, the incidence among adolescents 10-14 and 15-19 years of age increased. Implementation of school requirements through 10th grade in WP may explain the differences in the decline in incidence among adolescents. Continued surveillance will be important to monitor the impact that the 2-dose vaccine policy in children has on varicella epidemiology.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors.forename: Dalya
authors.initials: D
authors.lastname: Guris
authors.forename: Aisha O
authors.initials: AO
authors.lastname: Jumaan
authors.forename: Laurene
authors.initials: L
authors.lastname: Mascola
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Watson
authors.forename: John X
authors.initials: JX
authors.lastname: Zhang
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Chaves
authors.forename: Paul
authors.initials: P
authors.lastname: Gargiullo
authors.forename: Dana
authors.initials: D
authors.lastname: Perella
authors.forename: Rachel
authors.initials: R
authors.lastname: Civen
authors.forename: Jane F
authors.initials: JF
authors.lastname: Seward
mesh_terms: D000293:Adolescent; D000328:Adult; D002140:California / Q000453:epidemiology; D002644:Chickenpox / Q000453:epidemiology* / Q000517:prevention & control; D019433:Chickenpox Vaccine / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D010414:Pennsylvania / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods*; D014481:United States / Q000453:epidemiology
chemical_list: D019433:Chickenpox Vaccine