LAUSR

The popularization of vaccination since the end of the XIXth century and the discovery of therapeutic drugs against bacterial, fungal and protozoan infections in the early XXth century led to the hope that the burden caused by infectious diseases could be ended. This culminated in the 1960s with the infamous, but most likely apocryphal, quote from a surgeon general of the United States stating that it was ‘time to close the book on infectious diseases’ (Spellberg & TaylorBlake, 2013). The emergence or reemergence of viral threats, starting with HIV but more recently with Ebola, Chikungunya and Zika viruses in humans and footandmouth disease virus and begomoviruses in agricultural animals and plants, as well as the generalization of drug resistance mutations, shattered this optimistic view. Furthermore, because of economic constraints, parasites always remained a major threat in many countries of the world. Somehow paradoxically, the current COVID19 pandemic is giving rise again to the hope of eradicating infectious diseases. This is largely motivated by the success in discovering, manufacturing, and implementing safe and efficient SARSCoV2 vaccines in less than a year. That some of the most widely used of these vaccines rely on newer RNA technology further stimulates optimistic predictions. From a history of science perspective, the view traces back to Paul Ehrlich's ‘magic bullet’ reference to highly accurate therapies, since RNA vaccines can be designed to target specific motifs. Their production is also much more rapid than traditional proteinbased vaccines. Their implementation is perhaps the only negative point, with a current necessity to store RNA vaccine doses at −80°C, which is prohibitively expensive in many healthcare settings. Are RNA vaccines fundamentally changing the equation? Is the bold 1960'sera vision of eradicating diseases now within our grasp? Evolutionary biologists and ecologists can bring valuable insights based on decades of experience analysing how microbes adapt to anthropic perturbations. In fact, the main reason why RNA vaccines were needed so rapidly is probably due to a virus spillover from an animal reservoir into the human population, a phenomenon that has been studied by evolutionary ecologists (LloydSmith et al., 2009). As illustrated by this special issue Virus evolution on the mutualist— parasite continuum, it is important to bear in mind that virus population have a huge diversity, a wide array of potential hosts, and that they are not always pathogenic. Furthermore, viruses evolve rapidly, implying that they can readily colonize new hosts or face changing environmental conditions. Importantly, by doing so, they modify the selective pressures that act on their evolution. In other words, public health policies should not only be designed to target current viruses but rather evolving viruses and this is why our community has a role to play.