Pregnant Patients with Varicella Immunity and Exposure to Chicken Pox
A pregnant patient who has had chicken pox and is immune does not need any intervention if exposed to a chicken pox case, as they already have protective immunity against varicella-zoster virus (VZV).
Understanding Varicella Immunity in Pregnancy
- Evidence of immunity to VZV includes laboratory evidence of immunity, laboratory confirmation of disease, or a history of varicella diagnosed by a healthcare professional 1
- Previous infection with varicella (chicken pox) provides long-lasting immunity against reinfection 1
- Serologic studies from the pre-vaccine era showed that 95.5-99.6% of adults had immunity to VZV by age 20-40 years 1
Risk Assessment for Immune Pregnant Women
- Pregnant women with documented immunity to varicella do not require any post-exposure prophylaxis or monitoring when exposed to VZV 2, 3
- The Centers for Disease Control and Prevention does not recommend any intervention for VZV-immune pregnant women after exposure to chicken pox 2
- Unlike primary varicella infection which poses significant risks during pregnancy, exposure in immune individuals does not lead to reinfection or complications 4, 5
Potential Concerns and Management
- Varicella-zoster immune globulin (VZIG) is only recommended for VZV-susceptible pregnant women within 96 hours after exposure to VZV 1, 3
- Post-exposure prophylaxis with VZIG is not needed for pregnant women with evidence of immunity 2, 6
- The risk of congenital varicella syndrome only exists with primary maternal infection during pregnancy, not with exposure in immune mothers 2, 5
Special Considerations
- If there is any uncertainty about immune status, serologic testing can confirm immunity 1
- Commercial assays are available to detect VZV antibodies, though they may not be necessary if there is clear documentation of previous infection 1
- Healthcare providers should document varicella immunity status for all pregnant women as part of routine prenatal care 6
Recommendations for Different Scenarios
- For pregnant women with unknown immune status who are exposed to varicella, serum testing should be performed 6
- If serum results are negative or unavailable within 96 hours from exposure, VZIG should be administered 6
- For immune pregnant women, no specific precautions are needed after exposure to chicken pox 2, 3
Prevention Strategies
- Vaccination against varicella is recommended for all non-immune women as part of pre-pregnancy care, but should not be administered during pregnancy 6
- Household contacts of pregnant women should be vaccinated against VZV if they have no history of chickenpox and are seronegative for HIV 1
- A pregnant mother in the household is not a contraindication for immunization of a child in the household 1
In conclusion, while varicella infection during pregnancy can pose serious risks to both mother and fetus, these concerns do not apply to pregnant women who are already immune to chicken pox through previous infection.