Varicella Outbreak in a Child Day Care Center, Hsinchu County, January 2013

Yung-Ching Lin1, Hsuan-Chu Lin2,Chia-Ping Su2, Ming-Chih Liu1,Wan-Chin Chen1

2013 Vol.29 NO.12

Correspondence Author: Yung-Ching Lin

  • 1.Office of Preventive Medicine, Centers for Disease Control, Taiwan
  • 2.Second Branch, Centers for Disease Control, Taiwan


       Five varicella cases, including four children and one teacher (age range: 1 year 5 months – 29 years) in a child day care center in Hsinchu county were reported within a month during 2012 – 2013. The overall attack rate was 6%. After investigating the incubation period, communicable period, and possible exposure period of the cases, varicella outbreak was confirmed. Case 1 (index case, primary case of varicella infection) probably transmitted varicella to case 2 (secondary infection) and case 3, 4, and 5 became infected from case 2 (tertiary infections). We conducted contact investigation of the contacts in the child day care center, including the children and staff, and assessed staff pregnancy status, chickenpox infection history and immunization record. Environmental investigation showed that the probable site of disease transmission was the pick-up area on the first floor. Our control measures included case isolation and follow-up, contact tracing and education for the children and staff in the center, and investigation and contact tracing of the contacts in families and the clinic. For varicella outbreak investigations, we recommend that public health authorities and associated organizations should monitor high-risk contacts closely, especially pregnant women, and consider using post-exposure prophylaxis. Knowledge on varicella infections and immunity should also be strengthened for staff in child day care centers and high-risk populations to prevent future varicella outbreaks.