neonatal chickenpox

Last edited 05/2022 and last reviewed 05/2022

Neonatal chickenpox is an infection with significant mortality.

  • note that if maternal chickenpox occurs from 1 week before birth to 4 weeks after then there is a risk of severe infection in the infant
  • antivirals are now recommended for post-exposure prophylaxis for all at risk groups apart from susceptible neonates exposed within one week of delivery (either in utero or post-delivery) (1)
    • VZIG (varicella zoster immunoglobulin) is recommended for those for whom oral antivirals are contraindicated
  • exposed infants who receive VZIG should be observed for signs of infection for 28 days after the onset of maternal disease since VZIG may prolong the incubation period of the virus for up to 28 days (2)
  • zoster immunoglobulin is also recommended for varicella zoster antibody negative infants exposed to chickenpox or herpes zoster in the first 7 days of life
  • note that zoster immunoglobulin is not required for infants where the maternal antibody will be present. These include:
    • where maternal chickenpox had an onset more than 7 days before the infant was born
    • where the mother has a positive history of chickenpox and/or a positive varicella zoster antibody status
    • where the mother develops herpes zoster before or after delivery
  • about 50% of neonates will become infected if exposed to maternal varicella despite zoster immune globulin prophylaxis (3)
  • in up to 2/3 of infants infected with varicella, the infection is asymptomatic or mild. However, rarely fatal cases have been reported despite administration with zoster immunoglobulin in those with the onset of maternal chickenpox up to 4 days before delivery to 2 days after. It is recommended that early treatment with intravenous acyclovir should be used for infants in this exposure category who develop chickenpox - whether or not they have had varicella immune globulin prophylaxis (4)

Notes (4):

  • a Drug and Therapeutics review quoted criteria for administration of varicella immune globulin. This regime has been used in prospective observational studies that have shown varicella globulin vaccination may attenuate infection:
    • their mother's rash develops between 7 days before and 7 days after birth;
    • they were born within the last 7 days, their mother is seronegative and they have had significant non-maternal post-natal exposure (e.g. from a sibling);
    • they have been exposed to chickenpox and are at risk because of potentially inadequate transfer of maternal antibodies. This includes babies born before 28 weeks gestation; or weighing less than 1,000g; or who have had repeated blood sampling with replacement by packed red cell infusion; or those requiring intensive or prolonged special care nursing

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