  Corrections to elastic moduli, including the effective shear modulus, of a
solid neutron star crust due to electron screening are calculated. At any given
mass density, the crust is modelled as a body-centred cubic Coulomb crystal of
fully ionized atomic nuclei of a single type with a polarizable
charge-compensating electron background. Motion of the nuclei is neglected. The
electron polarization is described by a simple Thomas-Fermi model of
exponential electron screening. The results of numerical calculations are
fitted by convenient analytic formulae. They should be used for precise neutron
star oscillation modelling, a rapidly developing branch of stellar seismology.
