Neonatal varicella and early-onset herpes zoster following maternal infection at term: a case report.

backgroundVaricella infection during late pregnancy is uncommon but can lead to serious complications for the neonate, including neonatal varicella and, rarely, early-onset herpes zoster. Standard management includes postnatal separation, administration of intravenous immunoglobulin, and antiviral treatment when indicated. However, prophylaxis may not always prevent infection or reactivation, especially in cases where maternal immunity is absent. CASE PRESENTATION: In March 2024, a 35-year-old Iranian pregnant woman who developed varicella at 37 weeks of gestation presented. She was treated with oral acyclovir (400 mg three times daily), and cesarean delivery was performed 5 days later under strict infection control protocols. Serologic testing confirmed low maternal varicella zoster virus immunoglobulin G levels, indicating no prior immunity. The newborn, an early-term female (weight = 2860 g), was delivered healthy and admitted to the neonatal intensive care unit in isolation. On day 2 of life, she received 1 g of intravenous immunoglobulin (~350 mg/kg) as prophylaxis despite being asymptomatic. However, at 16 days of age, she developed vesicular lesions (typical varicella lesions) and was hospitalized and treated with intravenous acyclovir. She was later switched to an oral formulation. At 6 months of age, the infant presented with herpes zoster, despite no known contact with infected individuals. She was treated with oral acyclovir and recovered fully. No developmental delays or neurologic complications were observed at 1-year follow-up.

conclusionThis case highlights that neonatal varicella can occur despite intravenous immunoglobulin prophylaxis and strict isolation, and early-onset herpes zoster may follow perinatal exposure. Close follow-up of exposed neonates is crucial, and further research is needed to better understand the protective efficacy of intravenous immunoglobulin and the mechanisms of early varicella zoster virus reactivation in infancy.