The combined effect of the magnetic field background in the form of a singular vortex and the Dirichlet boundary condition at the location of the vortex on the vacuum of quantized scalar field is studied. We find the induced vacuum energy density and current to be periodic functions of the vortex flux and holomorphic functions of the space dimension. * E-mail: yusitenko@gluk.apc.org 379 Mod. Phys. Lett. A 1998.13:379-386. Downloaded from www.worldscientific.com by UNIVERSITY OF CALIFORNIA @ DAVIS on 02/03/15. For personal use only.