Updated recommendations advise clinicians that varicella zoster immune globulin can be given up to 10 days after exposure to the virus with the same effectiveness as when used within the previously recommended 4-day window.
The update from the Centers for Disease Control and Prevention (CDC) addresses the use of VariZIG, a purified immune globulin preparation made from human plasma containing high levels of antivaricella zoster virus antibodies. The product is used in the United States for postexposure prophylaxis of varicella in individuals at high risk of severe disease who don’t have evidence of immunity to varicella and can’t take the varicella vaccine.
Expanded Window for VariZIG. JAMA. 2013;310(10):1017. doi:10.1001/jama.2013.276459