Congenital and Neonatal Varicella
Background
Varicella in pregnancy may cause spontaneous abortion or premature
delivery. If the infection occurs in the first 20 weeks of gestation, the fetus
may be affected. The literature suggests the risk of embryopathy is
approximately 0.4% when maternal infection occurs before 13 weeks and 2%
when it occurs between 13 and 20 weeks gestation. Fetuses exposed to
varicella also have between 0.8 and 1.7% risk of developing herpes zoster in
the first two years of life. When maternal varicella occurs in the four weeks
before delivery, fetal infection rate is high and infants may develop varicella
after birth. Postnatal exposure may also cause neonatal varicella, which has
been considered to carry a high mortality, although no information on its
effects had been collected in Australia prior to this study.
Objectives
• To estimate the incidence and severity of congenital and neonatal varicella in Australia
• To estimate the potential benefits of vaccinating non-immune women prior to pregnancy
Case definition
Congenital varicella (including varicella embryopathy)
Any stillborn, newborn infant or child up to the age of 2 years who, in the opinion of the
notifying paediatrician, has definite or suspected congenital varicella, with or without
defects, based on history, clinical and laboratory findings.
Neonatal varicella
Any infant with clinical or laboratory-confirmed varicella, with onset in the first month of life,
and without features of varicella embryopathy. The infection may result from peripartum
maternal infection or postnatal exposure.
Results - 1997
In 1997 there were three confirmed cases of congenital varicella and 13 confirmed cases of
neonatal infection. Cases came from New South Wales (6), Queensland (5), Western
Australia (3) and Victoria (2). Maternal ages ranged from 21 to 34 years and seven cases
were first children.
Congenital varicella
In Western Australia, one pregnancy was terminated at 21 weeks because of hydrocephalus
following maternal varicella at 11 weeks gestation. Skin scars were found at autopsy.
Another mother had varicella at 16 weeks gestation in her second pregnancy. The child was
severely affected with neurological damage (encephalopathy, bulbar palsy, neurogenic
bladder), colonic atresia and skin scars, but had no eye defects. Varicella virus was isolated
from the infant, who also developed shingles at six weeks of age. In NSW, a mother had
varicella at eight weeks gestation. The infant was severely affected with limb, skeletal, heart
and nervous system defects, but had normal eyes. The child died at 12 days of age and at
autopsy varicella virus was found in the brain by polymerase chain reaction.
Neonatal varicella
Details of the 13 neonatal cases are shown in Table 12. Five mothers had varicella before
delivery, six had varicella after delivery and one had a varicella contact at term, but had no
illness. In one infant, the source of infection was unknown. Use of zoster immune globulin
(ZIG) in 10 children was associated with mild illness. Two of these children also received
acyclovir. One infant who did not receive ZIG and whose mother had contact with varicella at
term, but no illness, was the only case with a moderately severe illness. He was treated with
acyclovir.
