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

OBJECTIVES: To determine the seroconversion rate after varicella immunizati on of healthcare workers (HCWs) and the effect of seroconversion rate on cu rrent cost-based recommendations for universal vaccination. METHODS: A voluntary vaccination program for HCWs was performed at a tertia ry-care cancer center in New York City. A commercial latex agglutination as say was used to test postvaccination antibody response. Costs for vaccinati on 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. Th irty-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 recei ved 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 seronegat ive HCWs was estimated and compared to the cost of varicella-related furlou ghs at our institution. CONCLUSIONS: We found a considerably lower rate of vaccine-induced seroconv ersion at our hospital compared to that of the published literature. Despit e this finding, universal varicella vaccination remained an extremely cost- effective alternative to the furloughing of exposed, seronegative HCWs. Pro jected hospital savings exceeded $53,000 in the first year after vaccinatio n alone.