Varicella zoster virus antibody titers after intravenous zoster immune globulin in neonates, and the safety of this preparation

Abstract

1) To assess the safety of intravenous varicella zoster virus hyperimmune globulin G (IV-VZVIG) in neonates; 2) measure varicella zoster virus-specific IgG antibody (VZVIG) changes in newborn IV-VZVIG recipients. Eighteen neonatal intensive care unit (NICU) neonates with varicella exposure were given 1 ml/kg (43 International Units (IU)/kg) Varitect IV-VZVIG. Serum VZVIG titers were assayed in neonatal recipients 0, 1, 7, 14, 21, 28, and 35 d after IV-VZVIG. Also, serum samples for VZV-IgM antibody determinations were obtained at 4 wk post-infusion. No varicella developed in the 18 infants. Infusion of 1 ml/kg (43 IU/kg) IV-VZVIG was generally safe. The IV-VZVIG dose resulted in seroconversion of a non-immune newborn. Five infants had low basal VZVIG titers, and two of them had a 0.6-log10 increase at 24 h post-infusion. Neonatal VZVIG titers (mean+/-SEM in log(10)) before IV-VZVIG and after by 1, 7, 14, 21, 28, and 35 d were 2.22+/-0.15, 2.17+/-0.17, 2.02+/-0.12, 0.87+/-0.2, 1.09+/-0.19, 2.33+/-0.07, and 2.16+/-0.1, respectively. One ml/kg (43 IU/kg) IV-VZVIG was generally safe. Our neonatal mean VZV-immune status did not significantly increase after the 1 ml/kg (43 IU/kg) IV-VZVIG dose, although no varicella developed and it caused a VZV-specific seroconversion.