  We describe a model for pion production off nucleons and coherent pions from
nuclei induced by neutrinos in the 1 GeV energy regime. Besides the dominant
Delta pole contribution, it takes into account the effect of background terms
required by chiral symmetry. Moreover, the model uses a reduced
nucleon-to-Delta resonance axial coupling, which leads to coherent pion
production cross sections around a factor two smaller than most of the previous
theoretical estimates. Nuclear effects like medium corrections on the Delta
propagator and final pion distortion are included.
