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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Varicella in Pregnancy
8. What about the varicella vaccine?
Since the varicella vaccine is a live attenuated viral preparation it is
contraindicated in pregnancy. Nevertheless, a registry of pregnant vaccine
recipients has shown no incidence of subsequent adverse fetal effects, so
reassurance is appropriate. Since manufacture of VZIG has been discontinued,
CDC reported an unlicensed product VariZIG is available under an
investigational new drug application. With the anticipated difficulties in obtaining
VariZIG in a timely fashion, it is even more important to vaccinate children and
non-immune non-pregnant adults.
So, to review, primary varicella infection during the first 20 weeks of gestation
causes congenital varicella syndrome (eg, limb hypoplasia, microcephaly, dermal
scarring, ocular defects) in two percent of fetuses. Maternal infection from five
days before to two days after delivery results in neonatal disease in 17 to 30
percent of offspring. In addition, maternal disease is uncomfortable and can be
associated with severe maternal complications.
As with other live vaccines, varicella vaccine should not be administered to
pregnant women and pregnancy should be avoided for one month following each
dose of vaccine. In adults, a positive history of varicella is 97 to 99 percent
predictive of serologic immunity. A strategy of selectively serotesting women with
a negative or uncertain history of chickenpox followed by vaccination of
seronegative women may be a cost-effective policy for reducing perinatal and
maternal morbidity.
The CDC recommends vaccination of nonpregnant women without evidence of
immunity who do not plan to become pregnant within the next month. Evidence
of immunity to varicella in this population includes any of the following: (1)
documentation of 2 doses of varicella vaccine at least 4 weeks apart, (2) history
of varicella based on diagnosis or verification of varicella by a health-care
provider; (3) history of herpes zoster based on health-care provider diagnosis; or
(4) laboratory evidence of immunity or laboratory confirmation of disease.
As with other live vaccines, varicella vaccine should not be administered to
pregnant women and pregnancy should be avoided for one month following each
dose of vaccine. Other live viruses (live nasal influenza vaccine or MMR should
be administered the same day as the varicella vaccine or at least 4 weeks
afterwards)
A VARIVAX registry has been created to track pregnancy outcomes when
vaccination occurred within three months of or during pregnancy (1-800-986-
8999). As of March 2000, no cases of congenital varicella syndrome had been
identified among the offspring of varicella negative women immunized during the
first or second trimester (n = 56), third trimester or within one month of the last
menstrual period (LMP) before conception (n = 15), or more than one month
before this LMP (n = 14). While reassuring, these data are too limited to assure
safety of vaccine administration during pregnancy. However, varicella vaccination
during pregnancy should not be considered an indication for pregnancy
termination.
Breastfeeding
Breastfeeding is not a contraindication for varicella vaccination of the mother or
child. No evidence exist to validate concerns about the potential presence of live
viruses from vaccines in maternal milk if the breastfeeding mother is vaccinated.
There are minimal data regarding the safety of breastfeeding after varicella
immunization. A study of 12 nursing mothers given varicella vaccine postpartum
did not detect varicella DNA in samples of postvaccination breast milk and none
of their infants seroconverted or had evidence of varicella virus DNA. Varicella
vaccine may be considered for a nursing mother, extrapolating from this study
and the observation that no harm has been demonstrated from other live
attenuated vaccines given to lactating women.
Risk for transmission
Recently vaccinated healthy individuals rarely transmit the vaccine virus to close,
susceptible contacts. (Huang) The risk for transmission is higher when vaccinees
are immunocompromised and develop a varicella-like rash. However, routine
immunization of the children of pregnant susceptible women is not
contraindicated and should be encouraged because the potential risk of
transmission of vaccine virus is probably smaller than the known risks from
transmission of natural virus from unimmunized children who develop
chickenpox. The benefits and risks of varicella immunization of children of
pregnant women should be discussed with patients on a case-by-case basis.
Please see Prenatal Assessment and Postpartum Vaccination
