Varicella-Zoster Virus Globulin: New CDC Recommendations

Tinker Ready

July 22, 2013

The Centers for Disease Control and Prevention (CDC) has updated recommendations for the use of varicella-zoster immune globulin (VariZIG) to reduce the severity of infection by varicella-zoster virus (VZV), which causes chickenpox in children and shingles in adults.

The recommendations extend the window for postexposure prophy¬laxis for those at high risk for severe varicella. The US Food and Drug Administration's (FDA's) original approval of VariZIG as an investigational new drug recommended use within 4 days, but subsequent studies have shown that the treatment is effective for up to 10 days after exposure, according to updated advice published in the July 19 issue of the Mortality and Morbidity Weekly Report.

After a review, the CDC's Advisory Committee on Immunization Practices has endorsed the expanded use. The CDC guidelines now mirror those adopted by the American Academy of Pediatrics and the FDA.

VariZIG is an antibody preparation manufactured from the plasma of healthy donors with high anti-VZV antibody levels. It is the only FDA-approved varicella zoster immune globulin preparation in the United States. The CDC now calls for the use of VariZIG "as soon as possible after exposure to varicella-zoster virus and within 10 days."

The CDC recommends VariZIG for patients "without evidence of immunity to varicella who are at high risk for severe varicella and complications, who have been exposed to varicella or herpes zoster, and for whom varicella vaccine is contraindicated." It is administered in 2 or more injections, depending on a patient's weight.

Before administering the drug, health professionals need to consider 3 factors, according to the CDC: evidence of a lack of immunity to varicella, the risk for infection, and risk for varicella com-plications.

In addition to expanding the treatment window, the new guidelines amend recommendations by calling for VariZIG treatment for premature infants exposed to the virus any time during inpatient care for their prematurity. Previous guidelines call for VariZIG only for neonatal exposures.

"Because the immune systems of premature infants (some of whom might be extremely low birthweight and spend months in neonatal intensive care units) might be compromised, they are considered, on the basis of expert opinion, at high risk for severe varicella."

The document also recommended VariZIG for the following groups:

  • immunocompromised patients without evidence of immunity;

  • newborn infants whose mothers have varicella symptoms between 5 days before and 2 days after delivery;

  • hospitalized premature infants born at 28 weeks of gestation or later whose mothers do not have evidence of immunity to varicella;

  • hospitalized premature infants born at less than 28 weeks of gestation or who weigh less than 1000 g at birth, regardless of their mothers' evidence of immunity to varicella; and

  • pregnant women without evidence of immunity.

The document notes that the demand for VariZIG has declined, along with the drop in incidence of chickenpox, but that exposure still occurs.

Morb Mortal Wkly Rep. Published online July 19, 2013. Full text

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