Varicella-zoster infection after allogeneic bone marrow transplantation: incidence, risk factors and prevention with low-dose aciclovir and ganciclovir

We examined the incidence of herpes varicella-zoster virus (VZV) infection in 151 patients undergoing allogeneic BRIT between August 1990 and Septembe r 1997 and who survived at least 3 months. Median follow-up was 17 (range 3 .3-80.7) months. Herpes simplex virus antibody positive (HSV+) patients rec eived aciclovir 1200 mg p.o. daily or 750 mg i.v. daily, in divided doses f rom day 0 to engraftment, Ganciclovir (5 mg/kg i.v. three times per week) w as given in CMV+ patients (or if the donor was CMV+) from engraftment to da y 84. Ganciclovir was continued or recommenced if a dose of greater than 20 mg of prednisone was used for the treatment of GVHD otherwise aciclovir wa s recommenced. In HSV+ patients not receiving ganciclovir, aciclovir 600 mg p.o. daily in divided doses was given until at least 6 months after BAIT. Thirty-two patients developed VZV infection from 4.1 to 28 months after tra nsplant, The estimated cumulative incidence of VZV was 13% (95% confidence interval 6-19%) at 12 months, 32% (22-42%) at 24 months and 38% (27-50%) at 28 months, with no further cases beyond that time. No patient developed VZ V whilst receiving aciclovir or ganciclovir (P < 0.0001). However, there wa s a rapid onset of VZV following cessation of antriviral therapy (33% (20-4 6%) at 1 year post cessation). The presence of GVHD and the prior duration of antiviral prophylaxis were significant and independent risk factors for the development of VZV. Age, underlying disease, conditioning therapy or do nor type were not. We conclude that 3-6 months of low-dose aciclovir and ga nciclovir are effective at delaying the onset of VZV after allogeneic BRIT, but may not affect the overall incidence of infection. Prolonged prophylax is may be warranted in patients at high risk of infection, for example thos e patients with GVHD.