A varicella outbreak in a school with high one-dose vaccination coverage, Beijing, China☆

Details

• Alternative Title:
  Vaccine
• Personal Author:
  Lu, Li ; Suo, Luodan ; Li, Juan ; Zhai, Lijun ; Zheng, Qingxiu ; Pang, Xinghuo ; Bialek, Stephanie R. ; Wang, Chengbin
• Description:
  Background
  
  Varicella vaccine is available in the private sector in China, with a single dose currently recommended for children aged ≥12 months. We investigated a varicella outbreak in a school in Beijing with high varicella vaccination coverage to describe the outbreak, examine risk factors for vaccine failure, and calculate vaccine effectiveness.
  
  Methods
  
  A varicella case was defined as an acute generalized maculopapular rash without other apparent cause in a student without prior varicella attending the elementary school during August 30–December 28, 2010. Varicella among vaccinated students (breakthrough varicella) was defined as varicella occurring >42 days after vaccination. Students’ vaccination status was verified with immunization records and clinical presentations were collected from health care practitioners.
  
  Results
  
  Of the 951 students, 934 (98%) had no prior varicella history. Among these students, 916 had received 1 dose of varicella vaccine and 2 had received 2 doses (98% vaccination coverage) before the outbreak. A total of 87 cases occurred during the outbreak; most had breakthrough varicella (86/87, 99%) and mild disease (83/87, 95%). Age at vaccination (<15 months vs.≥15 months) and time since vaccination before outbreak (<5 years vs. ≥5 years) were not associated with development of breakthrough varicella. Single-dose varicella vaccination was 89% effective in preventing any varicella and 99% in preventing moderate/severe varicella.
  
  Conclusion
  
  Single-dose varicella vaccination is highly effective in reducing varicella incidence and mitigating disease severity, but not high enough to prevent outbreak. A two-dose program might help to prevent varicella outbreaks in Beijing.
  
  
• Subjects:
  Chickenpox Chickenpox Vaccine Child Child, Preschool Disease Outbreaks Female Herpesvirus 3, Human Humans Male Risk Factors Schools Students Time Factors Vaccination

  More +
• Source:
  Vaccine. 30(34):5094-5098
• Pubmed ID:
  22687763
• Pubmed Central ID:
  PMC4620431
• Document Type:
  Journal Article
• Funding:
  CC999999/ImCDC/Intramural CDC HHSUnited States/
• Place as Subject:
  China
• Volume:
  30
• Issue:
  34
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:2e30cb807d85566a4e286c5cf5b90a3cd93e6cdac845879bd269d82437dff23e
• Download URL:
  https://stacks.cdc.gov/view/cdc/35341/cdc_35341_DS1.pdf
• File Type:
  [PDF - 724.00 KB ]