Evolution of Viruses in Immunized Populations of Vertebrates

Scientists have described thousands of species of viruses, many of which are pathogens of vertebrates. Given that vertebrates have their highly sophisticated adaptive immune systems capable of memorizing pathogens, interaction with such systems should theoretically be one of the most important factors influencing the evolution of viruses. The review focuses on how acquired immunity (infection-induced and vaccine-induced) affects the most important medical characteristics of viral pathogens—transmissibility, infectivity, and virulence. Both known real examples of the evolution of viruses in immunized populations and theoretical articles and the results of mathematical modeling are considered. Special attention is paid to the SARS-CoV-2 pandemic. Methodological recommendations are given for creating vaccines and conducting vaccination campaigns in the light of the raised evolutionary issues.