Drug Interaction Report

ADJUST DOSING INTERVAL: Concomitant administration of pneumococcal 23-valent vaccine may reduce the immunogenicity of varicella-zoster virus (VZV) vaccine. The mechanism of interaction has not been described. In a randomized, double-blind, controlled clinical trial consisting of 473 adults sixty years of age or older, VZV antibody levels were significantly lower in the subjects who received both vaccines concurrently than in those who were given VZV vaccine four weeks after the pneumococcal 23-valent vaccine. At four weeks postvaccination, VZV antibody geometric mean titers were 338 gpELISA units/mL for the concomitant group and 484 gpELISA units/mL for the sequential group (GMT ratio = 0.70).

MANAGEMENT: Varicella-zoster virus vaccine and pneumococcal 23-valent vaccine should not be given concurrently. If possible, these vaccines should be administered at least four weeks apart.