Seroconversion rates in healthcare workers using a latex agglutination assay after varicella virus vaccination.

Overview

OBJECTIVES: To determine the seroconversion rate after varicella immunization of healthcare workers (HCWs) and the effect of seroconversion rate on current cost-based recommendations for universal vaccination. METHODS: A voluntary vaccination program for HCWs was performed at a tertiary-care cancer center in New York City. A commercial latex agglutination assay was used to test postvaccination antibody response. Costs for vaccination and postvaccination serological testing were compared to potential costs of postexposure employee furloughs. RESULTS: Of 263 seronegative HCWs, 96 (36.5%) began the vaccine program. Thirty-nine HCWs received only one dose of vaccine. Seven returned for follow-up antibody testing, of whom 4 were seropositive. Of the 57 HCWs who received two doses, 38 returned for follow-up serology. Thirty-one (81.6%) HCWs were seropositive for varicella-zoster virus antibodies, and seven HCWs (18.4%) remained seronegative. Total cost of vaccination for all 263 seronegative HCWs was estimated and compared to the cost of varicella-related furloughs at our institution. CONCLUSIONS: We found a considerably lower rate of vaccine-induced seroconversion at our hospital compared to that of the published literature. Despite this finding, universal varicella vaccination remained an extremely cost-effective alternative to the furloughing of exposed, seronegative HCWs. Projected hospital savings exceeded $53,000 in the first year after vaccination alone.