Before revision:  In this paper, we study the effects of clustering on the spread of sequential strains of a pathogen using the generating function formulation under a complete cross immunity coupling. We derive conditions for the epidemic threshold of the first strain and the threshold of coexistence of the second strain.
After revision:  In this paper, we study the effects of clustering on the spread of sequential strains of a pathogen using the generating function formulation under a complete cross-immunity coupling, deriving conditions for the epidemic threshold of the first strain and the threshold of coexistence of the second strain.