  We propose a fully cooperative coinfection model in which singly infected
individuals are more likely to acquire a second disease than those who are
susceptible, and doubly infected individuals are also assumed to be more
contagious than those infected with one disease. The dynamics of such fully
cooperative coinfection model between two interacting infectious diseases is
investigated through well-mixed and network-based approaches. We show that the
former approach exhibits three types of hysteresis, namely, $C$, $S_l$ and
$S_r$ types, where the last two types have not been identified before. The
first (resp., the second and the third) type exhibits (resp., exhibit)
discontinuous outbreak transition from the disease free (resp., low prevalence)
state to the high prevalence state when a transmission rate crosses a threshold
from the below. Moreover, the third (resp., the first and the second) type
possesses (resp., possess) discontinuous eradication transition from the high
prevalence state to the low prevalence (resp., disease free) state when the
transmission rate reaches a threshold from the above. Complete characterization
of these three types of hysteresis in term of parameters measuring the
uniformity of the model is also provided. Finally, we assess numerically this
epidemic dynamics in random networks.
