Varicella zoster immune globulin (human) (VARIZIG) in immunocompromised patients: a subgroup analysis for safety and outcomes from a large, expanded-access program.

backgroundImmunocompromised children and adults are at increased risk for severe disease and death following varicella zoster virus infection. Varicella zoster immune globulin (human) (VARIZIG) is recommended for post-exposure prophylaxis to prevent or attenuate varicella infection in high-risk individuals.

methodsAn open-label, expanded-access program provided VARIZIG to high-risk individuals exposed to varicella or herpes zoster. Immunocompromised participants were stratified by type of immunocompromising condition ("oncologic immunodeficiency", "primary immunodeficiency", "solid organ transplant" [SOT], "hematopoietic cell transplant" [HCT], and "other"). Patient characteristics, type of exposure and varicella outcome, and safety data were assessed.

resultsThis analysis included 40 adults (primary [n = 6] or oncologic [n = 10] immunodeficiencies, history of SOT [n = 5] or HCT [n = 6], and other [n = 13]), and 263 children (primary [n = 13] or oncologic [n = 152] immunodeficiencies, history of SOT [n = 36] or HCT [n = 17], and other [n = 45]). Among adults and children, 48% vs 72% were exposed to varicella, 38% vs 16% were exposed to herpes zoster, and 15% vs 12% had an unspecified exposure. Overall incidence of varicella infection in adults after VARIZIG use was 6%; incidence of varicella infection in children after VARIZIG use was 7%. Similar rates were noted in each subgroup. Most cases of varicella were mild, with two children developing > 100 lesions and no cases of varicella-related pneumonia or encephalitis. Varicella-related hospitalizations occurred primarily in children with oncologic immunodeficiencies. One serious adverse event (serum sickness) was considered related to VARIZIG and occurred in a child with oncologic immunodeficiency. There were no varicella- or VARIZIG-related deaths.

conclusionsThese data indicate that VARIZIG may reduce severity of varicella in immunocompromised children and adults.

trial registrationThis study was retrospectively registered with the public clinical trial identification NCT00338442 at https://www.clinicaltrials.gov on 20 June 2006.