  It is shown that fusion of neutrons and protons to He-4 nuclei occurs in
gamma-ray burst outflows in a process similar to big-bang nucleosynthesis in
the early Universe. Only the surviving free neutrons can then decouple
kinematically from the charged fluid so that the multi-GeV neutrino signal
predicted from inelastic nuclear n-p collisions is significantly reduced. It is
also argued that a sizeable fraction of ultra-high energy cosmic rays
accelerated in gamma-ray bursts should be He-4 nuclei.
