Mother-to-Child Transfer of Reactivated Varicella-Zoster Virus DNA and Varicella-Zoster IgG in Pregnancy.

Stress-induced subclinical reactivation of varicella-zoster virus (VZV) has been studied previously. However, subclinical reactivation of VZV induced by the stress of pregnancy has not been investigated. The objective was to study varicella DNA and varicella antibody levels in mothers and their newborn babies. VZV immunoglobulin G (IgG) levels in 350 mother-newborn dyads were studied using indirect enzyme-linked immunosorbent assay testing. A subset of 73 dyads was selected, DNA was isolated from the serum samples, and quantitative polymerase chain reaction (qPCR) was performed. Nearly 15% (14.6%) mothers tested were positive for varicella antibodies (>100 mIU/dL) and 16% were borderline (<100 and >50 mIU/dL). Approximately 16.9% of the babies were positive, and 18% were in borderline. Among those tested for VZV-DNA, 70% of mothers with low VZ-IgG (<100 mIU/dL) and 11.32% of those with high VZ-IgG (>100 mIU/dL) were positive for DNA. Among the newborns, 60% of those with low VZ-IgG and 15% of those with high VZ-IgG were positive for DNA. Mothers who have had VZV infection in the past can transmit VZV DNA to their babies.