Varicella Zoster Virus Infections in Pregnant Women and Neonates

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Varicella Zoster Virus Infections in Pregnant
Women and Neonates
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Diagnosis - pregnant woman

• A history of previous varicella infection is
  generally accepted as proof of immunity. But,
  when it can be done in a timely fashion,
  determination of immune status by ELISA is
  advisable before administration of VZIG
• Varicella infection is generally suspected from
  clinical presentation, although laboratory
  testing may be required for confirmation
• Serological testing is indicated when immunity to
  varicella must be determined, for example, when a
  past history is unreliable
• The presence of IgG antibody in the serum in
  absence of symptoms indicates previous infection.
  The detection of IgM with a rising IgG titre in
  maternal serum indicates a recent infection

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Prenatal diagnosis - pregnant woman

• As the risk of congenital varicella syndrome is
  low (1-2), the risk associated with the invasive
  prenatal diagnostic methods (amniocentesis or
  cordocentesis), suggests that they are unlikely
  to be a widely used diagnostic tool for
  congenital varicella syndrome
• Prenatal diagnosis of congenital varicella
  syndrome following maternal VZV infection may
  allow the woman to make an informed choice about
  termination of pregnancy
• Ultrasound screening between 19 and 23/24 weeks
  of gestation is recommended for all women with
  varicella in the first 21 weeks of pregnancy. If
  the sonographic findings are abnormal, fetal
  blood and amniotic fluid obtained in the 22nd to
  23rd weeks of gestation should be tested for VZV
  DNA, while testing for VZV-specific IgM in fetal
  blood is not helpful (2)

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Diagnosis in the newborn

• The diagnosis of varicella occurring in the
  newborn is usually based on clinical findings.
  The clinical course of varicella in newborns can
  vary in progression and severity

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Pre-exposure prophylaxis - vaccination

• Vaccination of seronegative women of childbearing
  age who are currently not pregnant should be
  considered (3)

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Post-exposure prophylaxis in pregnant woman

• VZIG should be administered as soon as possible
  to the seronegative mother following exposure to
  the virus in the first 20 weeks of gestation.
  VZIG may be administered to the susceptible woman
  who is exposed to VZV in the third trimester to
  reduce the risk of chickenpox (2)
• The value of post-exposure aciclovir prophylaxis
  for the susceptible pregnant woman should be
  assessed in clinical trials (R)

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Pregnant woman with varicella

• As the complications of varicella are more common
  in adults, given the limited Registry data
  available, there is no apparent reason to
  withhold aciclovir at any time in pregnancy (2).
  The dosage and route of administration is
  determined by the severity of disease. The woman
  should be advised about the use of a drug
  unlicensed in pregnancy.
• More data are required on long-term follow-up of
  children exposed to aciclovir in utero (R)

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Pregnant woman with varicella

• If a woman has severe or complicated disease
  (e.g. pneumonitis), iv aciclovir should be given
  (10 mg/kg every 8 hours for 7 days or longer) (3)
• Pregnant women with less severe disease should be
  treated with oral aciclovir (800 mg five time
  daily for 7 days) (3)
• The pregnant woman with varicella should avoid
  contact with all other pregnant women and
  neonates until her lesions are crusted

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Post-exposure prophylaxis in the neonate

• Administration of VZIG to the infant is advised
  if the mother develops varicella 7 days before or
  after delivery
• The neonate of a mother with active varicella
  should be isolated while in hospital, from birth
  to Day 21 (or Day 28 if the infant has been given
  VZIG), while neonates with congenital varicella
  syndrome do not need isolation from other
  children

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Treatment of the neonate

• Neonates exposed to varicella should be observed
  closely. If they develop vesicles, they should be
  treated early with iv aciclovir
• Occasionally, neonates may develop chickenpox
  despite receiving VZIG. This is usually mild, but
  therapy with aciclovir should be considered in
  these children

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Herpes zoster in the pregnant woman and neonate

• Herpes zoster is not a risk to the fetus
• Local guidelines for treating herpes zoster in
  adults should be followed

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Research initiatives for varicella

• Seroreversion in vaccinees should be monitored
  and the need for booster immunizations evaluated.
  (R)
• The neurodevelopmental effect of varicella in
  utero and herpes zoster early in life should be
  assessed. (R)
• As newer antivirals become available, their
  clinical efficacy in treating varicella-associated
  conditions in pregnant women and neonates should
  be evaluated (R)