From the Guidelines
Varicella-zoster immune globulin (VZIG) should be given to individuals at high risk for severe varicella infection who have been exposed to the virus and cannot receive the varicella vaccine, as soon as possible after exposure, ideally within 96 hours but can be given up to 10 days post-exposure, as recommended by the CDC 1. The primary candidates for VZIG include:
- Immunocompromised patients without evidence of immunity
- Pregnant women without immunity
- Newborns whose mothers developed varicella within 5 days before or 2 days after delivery
- Hospitalized premature infants (born before 28 weeks or weighing less than 1000g) regardless of maternal immunity status
- Premature infants whose mothers lack evidence of immunity VZIG works by providing antibodies against the varicella-zoster virus, offering temporary protection while the body's immune system responds to the exposure, as stated in the updated recommendations for use of VariZIG — United States, 2013 1. The standard dose is 125 units/10 kg body weight (minimum 125 units, maximum 625 units), administered intramuscularly, to provide passive immunity and help prevent or reduce the severity of infection in vulnerable individuals who could otherwise develop life-threatening complications from varicella. According to the CDC recommendations, administration of VariZIG as soon as possible after exposure to the varicella-zoster virus and within 10 days is crucial for greatest effectiveness 1. This approach is harmonized with the American Academy of Pediatrics (AAP) recommendations, ensuring a unified guideline for the use of VZIG in high-risk individuals 1.
From the Research
Reasons for Administering VZV Immunoglobulin
- VZV immunoglobulin is administered to reduce the risk of serious disease in individuals who have been exposed to the varicella-zoster virus, particularly in immunocompromised patients 2.
- The use of VZV immunoglobulin as post-exposure prophylaxis is considered when the time window for vaccination has expired or in cases where vaccination is not feasible 3.
- VZV immunoglobulin is used to prevent VZV infection in immunosuppressed patients, although antiviral agents such as acyclovir and valacyclovir can also be used as an alternative 4, 3.
Target Population for VZV Immunoglobulin
- Immunocompromised patients, including those with malignant diseases or undergoing immunosuppressive therapy, are at high risk of severe VZV infections and may benefit from VZV immunoglobulin administration 2, 4.
- Other high-risk individuals, such as elderly people, pregnant women, unvaccinated persons, infants, and immunocompromised children and adults, may also require post-exposure prophylaxis with VZV immunoglobulin 5.
Efficacy and Limitations of VZV Immunoglobulin
- The efficacy of VZV immunoglobulin in reducing the risk of serious disease is supported by some evidence, although the overall effect on disease rate and severity is only weakly documented 2.
- The use of VZV immunoglobulin is limited by its availability and the need for administration within a specific time window after exposure 3, 5.