In this paper, we propose an epidemic model with the transmission rate between susceptible and infected individuals, β, being time varying and piecewise constant. At any point in time, β is linked to a latent variable that follows a Hidden Semi-Markov Model (HSMM). This HSMM-driven epidemic Model (HSMM-EM) structures the data into multiple regimes, which greatly enhances decision-making capabilities, while the limited number of continuous model parameter guarantees straightforward model interpretation.