Varicella Zoster (VZV), Primary infection or Perinatal period

Note: If siblings at home have chicken pox and mother has positive chicken pox history, can send baby home. If negative maternal history, delay sending baby home until 7 days after onset of infection in siblings.

Potential Effect on Fetus

   Primary

• Congenital Syndrome especially:

  • limb hypoplasia

  • ocular abnormalities

  • CNS abnormalities

• Dermatomal scarring

   Perinatal period

• Chicken pox
  +/-
• Encephalitis

Rate of Perinatal Transmission

• Congenital VZV syndrome:

  • < 13 weeks – 1% risk

  • 13-20 weeks – 2% risk

NB: Neonatal VZV - if mother develops varicella < 5 days before to 2 days after delivery – 30% risk of neonatal fatality.

Maternal Screening

- Routine screening recommended if no history of chicken pox.
- If pregnant woman (with no history of previous chicken pox) is exposed, perform STAT Varicella IgG/IgM.
- If suspect primary infection, contact Virology lab re: VZV testing:

• DFA of lesions - best test
  or
• serology (IgG and IgM).

Prevention

- Non-immune women should be vaccinated before or after pregnancy (not during).
- Non-immune women exposed during pregnancy should receive VZIG (within 96 hours of exposure).
- If pregnant woman or neonate develops varicella, consult Infectious Diseases/Infection Control.
- Exposed neonate should receive VZIG prophylaxis.

(See Prophylaxis for Contacts of Communicable Diseases for VZIG indications.) If mother develops varicella < 5 days before to 2 days after delivery – give prophylactic acyclovir to baby.

- If severe neonatal VZV infection develops despite VZIG, start high dose acyclovir.