Which treatment is NOT effective for congenital varicella?

High-dose oral acyclovir is not an effective treatment for congenital varicella syndrome because the timing of maternal varicella infection during pregnancy significantly affects fetal outcomes. If the mother contracts varicella prior to the varicella-zoster immunization or during the first trimester, the risk of congenital varicella syndrome increases. Once fetal infection occurs, antiviral treatments like acyclovir have limited impact on the outcomes, particularly in relation to preventing the long-term effects of congenital varicella.

Supportive care remains the primary approach for managing congenital varicella, focusing on addressing symptoms and complications as they arise. Isolation can help prevent transmission of varicella to other individuals but does not treat congenital infection itself and is more relevant in managing acute varicella in a non-pregnant patient. Therefore, while supportive care and isolation play roles in management, high-dose oral acyclovir does not provide any meaningful benefit in the context of treating congenital varicella syndrome.