This article is from the Childhood Vaccinations FAQ, by Lynn Gazis-Sax email@example.com with numerous contributions by others.
Varicella or chickenpox is a highly contagious disease caused by
varicella zoster virus. Complications are rare in normal children, but
more common in children with immune deficiencies. The disease is
somewhat more severe in adults, and can be serious for newborns and
pregnant women. Possible (infrequent) complications include
hemorrhagic varicella, encephalitis, pneumonia, and bacterial skin
infection. Possible complications in pregnancy include premature birth
and congenital varicella, and mortality (of the infant, not the
mother) is high. "It is estimated that there are about 9,600
chicken-pox related hospitalizations annually, with 50 to 100 deaths."
(FDA announcement, January 28, 1994) Another risk, unfortunately on
the increase, is invasive group A streptococcal infections, to which
children ill with varicella may be susceptible.
A study of the effects of congenital varicella and herpes zoster
(Enders G; et al. Consequences of varicella and herpes zoster in
pregnancy: prospective study of 1739 cases. Lancet 1994 Jun 18;
343:1548-51., summarized in Journal Watch Summaries for July 1, 1994.)
followed 1373 women with varicella and 366 women with herpes zoster
acquired during the first 36 weeks of pregnancy. Nine of the infants
had congenital varicella syndrome, with defects ranging from
"multisystem involvement to limb hypoplasia and skin scars." There
were no cases of congenital varicella syndrome among infants whose
mothers had varicella after 20 weeks or among those whose mothers
received anti-varicella-zoster immunoglobulin after they were exposed.