1. Varicella Vaccine Effectiveness in Preventing Community Transmission in the 2-Dose Era.
- Author
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Perella D, Wang C, Civen R, Viner K, Kuguru K, Daskalaki I, Schmid DS, Lopez AS, Tseng HF, Newbern EC, Mascola L, and Bialek SR
- Subjects
- Adolescent, California epidemiology, Case-Control Studies, Chickenpox epidemiology, Chickenpox transmission, Child, Child, Preschool, Community-Acquired Infections epidemiology, Community-Acquired Infections transmission, Disease Transmission, Infectious prevention & control, Female, Humans, Male, Philadelphia epidemiology, Population Surveillance, Risk Factors, Severity of Illness Index, Surveys and Questionnaires, Chickenpox prevention & control, Chickenpox Vaccine administration & dosage, Community-Acquired Infections prevention & control, Immunization, Secondary
- Abstract
Objectives: We examined overall and incremental effectiveness of 2-dose varicella vaccination in preventing community transmission of varicella among children aged 4 to 18 years in 2 active surveillance sites. One-dose varicella vaccine effectiveness (VE) was examined in those aged 1 to 18 years., Methods: From May 2009 through June 2011, varicella cases identified during active surveillance in Antelope Valley, CA and Philadelphia, PA were enrolled into a matched case-control study. Matched controls within 2 years of the patient's age were selected from immunization registries. A standardized questionnaire was administered to participants' parents, and varicella vaccination history was obtained from health care provider, immunization registry, or parent records. We used conditional logistic regression to estimate varicella VE against clinically diagnosed and laboratory-confirmed varicella., Results: A total of 125 clinically diagnosed varicella cases and 408 matched controls were enrolled. Twenty-nine cases were laboratory confirmed. One-dose VE (1-dose versus unvaccinated) was 75.6% (95% confidence interval [CI], 38.7%-90.3%) in preventing any clinically diagnosed varicella and 78.1% (95% CI, 12.7%-94.5%) against moderate or severe, clinically diagnosed disease (≥50 lesions). Among subjects aged ≥4 years, 2-dose VE (2-dose versus unvaccinated) was 93.6% (95% CI, 75.6%-98.3%) against any varicella and 97.9% (95% CI, 83.0%-99.7%) against moderate or severe varicella. Incremental effectiveness (2-dose versus 1-dose) was 87.5% against clinically diagnosed varicella and 97.3% against laboratory-confirmed varicella., Conclusions: Two-dose varicella vaccination offered better protection against varicella from community transmission among school-aged children compared with 1-dose vaccination., (Copyright © 2016 by the American Academy of Pediatrics.)
- Published
- 2016
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