Ebola control: effect of asymptomatic infection and acquired immunity by Steve E Bellan, Juliet R C Pulliam, Jonathan Dushoff, and Lauren Ancel Meyers in The Lancet. Some people clearly have been infected with Ebola, yet do not get sick. However, it is not currently known whether individuals who are infected without getting sick are immune to reinfection and disease. If they are, then this observation has important implications both for being able to predict the scope of the epidemic, and for treatment. For example, if asymptomatic people are immune, then they could be recruited to be care providers. Recovered asymptomatic people could also be the source of life-saving transfusions. Despite these important implications, infected people who don’t develop symptoms are neglected in epidemiological models and in studies of immunity. The article by Bellan et al. is a call to action.