Prevalence and Characteristics of Pediatric Healthcare Workers without Immunity to Varicella zoster Virus.

This study aimed to determine the proportion of varicella non-immune pediatric healthcare workers (HCWs) of the Pediatrics Department of King Chulalongkorn Memorial Hospital and to determine cost-effective strategies for identifying non-immune personnel. A cross-sectional study using a self-administered questionnaire to determine HCWs' histories of chickenpox or 2-dose varicella vaccination was conducted. From a total of 699 HCWs, 653 HCWs (93%), including 145 physicians (22%), 297 nurses (46%), and 211 administrative staff (32%), responded to questionnaires. There were 475 HCWs (73%) who had a history of chickenpox, 58 (9%) who had completed the 2-dose varicella vaccine schedule, and 120 (18%) whose varicella-zoster virus (VZV) immunity status was uncertain. In total, 107 HCWs (89%) were tested for VZV IgG, 90 of whom had immunity, and 17 were determined to be non-immune. After combining history and VZV IgG test results, the prevalence of non-immune HCWs was 2.6% (95%CI 1.4-3.8), with those ≤40 years of age at higher risk of non-immunity. Implementing a strategy that involves testing of only those with an unknown VZV status and vaccination for only those determined to be non-immune costs 1,801 United States dollar (USD), less than the total cost (4,601 USD) for vaccinating all HCWs with uncertain status.