EARLY RECONSTITUTION OF IMMUNITY AND DECREASED SEVERITY OF HERPES-ZOSTER IN BONE-MARROW TRANSPLANT RECIPIENTS IMMUNIZED WITH INACTIVATED VARICELLA VACCINE

Varicella-zoster virus (VZV) causes herpes tester after bone marrow tr ansplantation (BMT). The immunogenicity of heat-inactivated varicella vaccine and effects on VZV pathogenesis were evaluated in 75 BMT patie nts randomized to receive vaccine or no intervention. Among 14 patient s given a single dose at 1 month after transplantation, the mean (+/-S E) stimulation index (SI) was 12.20 +/- 3.13 compared with 4.83 +/- 2. 74 (P = .036) in 14 unvaccinated patients, but clinical disease was no t altered. Among 24 patients vaccinated at 1, 2, and 3 months, mean SI was 8.43 +/- 3.89 versus 2.00 +/- 0.33 (P = .014) in 23 unvaccinated patients at 4 months and 8.56 +/- 2.81 versus 5.30 +/- 2.47 (P = .043) at 5 months. Disease severity associated with VZV reactivation was de creased dramatically in vaccinees given three doses; severity scores w ere 6.4 +/- 1.0 versus 11.8 +/- 1.1 (P = .007). This experience with v aricella vaccine in BMT patients is the first evidence that active imm unization can reduce morbidity due to herpesvirus reactivation in high -risk populations.