Pathogen evolution: Protective microbes act as a double-edged sword

Vaccines and infection can sometimes cause incomplete immunity, which allows for pathogen re-infection with decreased disease severity but also contributes to the evolution of pathogen virulence. A new study demonstrates that incomplete immunity from resident protective microbes results in similar evolutionary trajectories. Vaccines and infection can sometimes cause incomplete immunity, which allows for pathogen re-infection with decreased disease severity but also contributes to the evolution of pathogen virulence. A new study demonstrates that incomplete immunity from resident protective microbes results in similar evolutionary trajectories.