  Improving the numerical precision, dispersion corrections to the beam-normal
spin asymmetry which arise from the dominant nuclear excitations, are estimated
up to a collision energy of 1 GeV. A nonperturbative calculation of vacuum
polarization and the vertex plus self-energy correction, using optimized
potentials, indicates that for small scattering angles both these quantum
electrodynamical (QED) effects on the spin asymmetry decrease with energy above
200 MeV and can mostly be neglected at high energies. Examples are given for
the 12C and 208Pb nuclei. While our results disagree with the measured
high-energy spin asymmetry for 12C, they are able to explain the data on 208Pb
near 1 GeV.
