Varicella zoster virus infections following allogeneic bone marrow transplantation: frequency, risk factors, and clinical outcome.

Reactivation of varicella zoster virus (VZV) is a common event in patients undergoing allogeneic bone marrow transplantation (BMT) and may lead to life-threatening complications. We retrospectively analyzed the incidence, clinical outcome, and risk factors for VZV infections occurring within the first 5 years of transplantation in 100 consecutive adults undergoing allogeneic BMT between 1992 and 1997. Forty-one patients (41%) developed VZV reactivation a median of 227 days (range 45-346 days) post-transplantation. Twelve percent of VZV reactivation occurred in the first 100 days and 88% within the first 24 months. Among those who survived for 2 or more years after transplantation (n = 47), 59% developed VZV infection. Forty percent of patients with VZV reactivation required admission with a mean hospital stay of 7.2 days. Two patients developed encephalitis, and 1 died despite antiviral therapy. The most frequent complications were post-herpetic neuralgia and peripheral neuropathy (68%). Thoracic dermatomal zoster represented 41% of the infections; disseminated cutaneous involvement was observed in 17% of patients. No clinical or epidemiologic risk factors were associated with recurrence. Administration of ganciclovir for prevention of cytomegalovirus infection delayed the onset of VZV infection beyond 4 months (P = .06). In a further subset analysis, patients with a limited chronic graft-versus-host disease (GVHD) had a lower estimated incidence of VZV reactivation compared with those with extensive chronic GVHD (P = .11). We conclude that complications from reactivation of VZV infection are common and associated with considerable morbidity and mortality in patients undergoing allogeneic BMT.