In addition to understanding the nature of vaccination and treatment in shaping the course of the coronavirus epidemic, this paper also aims to clarify the role of population (or herd) immunity in formulating optimal treatment and vaccination policy.

This paper offers projections of future transmission dynamics for SARS-CoV-2 in an SEIRS model in which immunity is waning over time. The authors argue that research that relies significantly on the emergence of permanent immunity for individuals (and thus eventual herd immunity in the population) may give incomplete policy recommendations for how to navigate the...