What are the recommendations for varicella (chickenpox) prophylaxis in pregnancy and children?

From the Guidelines

For varicella prophylaxis in pregnancy and children, post-exposure prophylaxis with VariZIG (varicella-zoster immune globulin) is recommended within 10 days of exposure for susceptible pregnant women to reduce the risk of maternal and fetal complications, as stated in the guidelines by the Advisory Committee on Immunization Practices (ACIP) 1. The standard dose is 125 units/10 kg body weight, up to a maximum of 625 units, administered intramuscularly. For susceptible children, VariZIG is recommended for high-risk groups including:

• Immunocompromised children
• Newborns of mothers who developed chickenpox within 5 days before or 2 days after delivery
• Premature infants (<28 weeks or <1000g)
• Premature infants whose mothers lack immunity If VariZIG is unavailable, intravenous immune globulin (IVIG) at 400 mg/kg can be used as an alternative. For immunocompetent children without contraindications, varicella vaccination may be given within 3-5 days of exposure to prevent or modify disease. Acyclovir (20 mg/kg four times daily for 7 days, maximum 800 mg per dose) can be considered for high-risk exposed individuals when immune globulin is unavailable or beyond the 10-day window. Pregnant women without evidence of immunity who have been exposed to varicella should receive VZIG to prevent complications of varicella in the mother, rather than to protect the fetus, as noted in the guidelines 1. It is also recommended that neonates born to mothers who have signs and symptoms of varicella from 5 days before to 2 days after delivery should receive VZIG, regardless of whether the mother received VZIG 1. These interventions are critical because varicella infection during pregnancy can lead to congenital varicella syndrome or severe neonatal disease, while certain children face increased risks of severe or fatal varicella infections. Prenatal assessment of women for evidence of varicella immunity is recommended, and women who do not have evidence of varicella immunity should receive the first dose of vaccine before discharge from the health-care facility, with the second dose administered 4-8 weeks later, as recommended by the ACIP 1.

From the FDA Drug Label

Treatment of Chickenpox: Children (2 years of age and older):20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days. Children over 40 kg should receive the adult dose for chickenpox Adults and Children over 40 kg: 800 mg 4 times daily for 5 days.

The recommendations for varicella (chickenpox) prophylaxis in pregnancy are not directly addressed in the provided drug labels. For children, the recommended dose is 20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days for children 2 years of age and older, and children over 40 kg should receive the adult dose of 800 mg 4 times daily for 5 days 2.

From the Research

Varicella Prophylaxis in Pregnancy

• Varicella zoster immune globulin (VARIZIG) is recommended by the CDC for postexposure prophylaxis to prevent or attenuate varicella-zoster virus infection in high-risk individuals, including pregnant women 3.
• The administration of VARIZIG up to 10 days after varicella exposure in pregnant women has been shown to be effective in preventing or attenuating varicella-zoster virus infection 3.
• Varicella immunization is recommended for all non-immune women as part of pre-pregnancy and postpartum care, but varicella vaccination should not be administered in pregnancy 4.
• In the case of a possible exposure to varicella in a pregnant woman with unknown immune status, serum testing should be performed, and if the serum results are negative or unavailable within 96 hours from exposure, varicella zoster immunoglobulin should be administered 4.

Varicella Prophylaxis in Children

• Varicella zoster immune globulin (VARIZIG) is also recommended for postexposure prophylaxis in high-risk children, including immunocompromised children and preterm infants 3, 5.
• The live attenuated varicella vaccine is intended to mimic the tempo and nature of the humoral and cell-mediated immune responses to varicella infection, and two doses of varicella vaccine administered in childhood have been very effective in generating varicella-zoster virus (VZV) immune responses that prevent natural infection for at least several decades 6.
• Varicella vaccination is part of standard childhood immunization programs in many countries, and primary prevention includes vaccination against varicella infection 7.

Postexposure Prophylaxis

• Postexposure administration of VARIZIG was associated with low rates of varicella in high-risk participants, regardless of when administered within 10 days postexposure 3.
• Timely post-exposure prophylaxis of susceptible pregnant women with varicella zoster immunoglobulin is key to preventing chickenpox during pregnancy and its adverse fetomaternal sequelae 7.
• Varicella zoster immunoglobulin should be administered to neonates whenever the onset of maternal disease is between 5 days before and 2 days after delivery 4.