  We note that the theoretical prediction of neutrinos from gamma-ray bursts
(GRBs) by IceCube overestimates the GRB neutrino flux, because they ignore both
the energy dependence of the fraction of proton energy transferred to charged
pions and the radiative energy loss of secondary pions and muons when
calculating the normalization of the neutrino flux. After correction for these
facts the GRB neutrino flux is reduced, e.g., by a factor ~5 for typical GRB
spectral parameter, and may be consistent with the present zero event detected
by IceCube. More observations are important to push the sensitivity below the
prediction and test whether GRBs are the sources of ultra-high energy cosmic
rays.
