A comparison was made of antibody responses generated to live varicella (Oka/Merck) vaccine (Varivax) produced during three different manufacturing campaigns to evaluate the quality of the antibody responses and demonstrate consistency of the manufacturing process. Anti-varicella zoster virus (VZV) antibody titers were measured by an enhanced neutralization assay and VZV glycoprotein-based enzyme-linked immunosorbent assay (gpELISA). For sera taken from children who had received one dose of vaccine an excellent linear concordance in titers was observed between the two assays. Sera from adults who had received two doses demonstrated continuing increased neutralization at high gpELISA titers. The immunogenicity measured by the two assays demonstrates that the overall performance of the vaccine was very similar over the three production series.