Vaccine with narrow neutralization is predicted to accelerate the evolution of a rapidly-evolving virus

Some viruses persist in a population, because their rapid evolution allows them to escape recognition by antibodies in previously-infected individuals. To investigate parameters of effective vaccination against these viruses, a model of population structured according to virus variants that caused past or current infections is developed and informed from available data. Results demonstrate that vaccination against such viruses will accelerate virus evolution. Moreover, vaccination will increase the incidence of infection, i.e., has a negative efficacy, unless the immune response induced by the vaccine is broader antigenically than the response to natural infection. The critical vaccination frequency and coverage, at which the virus will become extinct, is inversely proportional to the square of the response breadth. These predictions set the quantitative criteria for the design of effective vaccines.