Viruses like influenza A and Ebola invade human cells in a number of steps. Research teams investigated the final stages of viral penetration using electron tomography and computer simulations. So-called fusion pores, through which the viral genome is released into the host cell, play a central role in these processes. If they can be prevented from forming, the virus is also blocked. The Heidelberg scientists describe previously unknown mechanisms, which might lead to new approaches to prevent infections.