Consistency of combining directed mutation networks with a single-memory evo-SIS model

Determine whether integrating a directed mutation network—constructed to reflect multiple immune memories and the suppression of re-emergent strains—into the evo-SIS framework that models each host with a single immune memory yields a consistent modeling formulation in general, and specify the conditions under which such a mixed approach is valid.

Background

The authors show how multiple immune memories can induce a strictly triangular (directed) mutation network that suppresses the re-emergence of older strains. Their main evo-SIS formulation, however, tracks a single immune memory per host.

They caution that mixing a directed mutation network (implied by multiple memories) with a single-memory host model may be inconsistent in general. Clarifying the theoretical consistency and scope of this mixed approach is necessary before employing it broadly for inference or prediction.