# Epidemiological Model Equations and Parameters
## SIR Model
### System of Equations
$$
\begin{cases}
\dot{S} = -\beta(1 - u)SI \\
\dot{I} = \beta(1 - u)SI - \gamma I & \forall t \in (0, t^*] \\
\dot{R} = \gamma I
\end{cases}
$$
### Initial Conditions
$$
[S(0), I(0), R(0)]^T = [S_0, I_0, R_0]^T
$$
### Parameters
- Basic Reproduction Number: $\mathcal{R}_0 = \frac{\beta}{\gamma}$
- Modified Reproduction Number: $\mathcal{R}_u = \frac{\beta(1 - u)}{\gamma}$
---
## SIS Model
### System of Equations
$$
\begin{cases}
\dot{S} = -\beta(1 - u)SI + \gamma I \\
\dot{I} = \beta(1 - u)SI - \gamma I & \forall t \in (0, t^*]
\end{cases}
$$
### Initial Conditions
$$
[S(0), I(0)]^T = [S_0, I_0]^T
$$
### Parameters
- Basic Reproduction Number: $\mathcal{R}_0 = \frac{\beta}{\gamma}$
- Modified Reproduction Number: $\mathcal{R}_u = \frac{\beta(1 - u)}{\gamma}$
---
## SIRD Model
### System of Equations
$$
\begin{cases}
\dot{S} = -\beta(1 - u)SI + \delta R \\
\dot{I} = \beta(1 - u)SI - (\gamma + \varepsilon)I & \forall t \in (0, t^*] \\
\dot{R} = \gamma I - \delta R \\
\dot{D} = \varepsilon I
\end{cases}
$$
### Initial Conditions
$$
[S(0), I(0), R(0), D(0)]^T = [S_0, I_0, R_0, D_0]^T
$$
### Parameters
- Basic Reproduction Number: $\mathcal{R}_0 = \frac{\beta}{\gamma + \varepsilon}$
- Modified Reproduction Number: $\mathcal{R}_u = \frac{\beta(1 - u)}{\gamma + \varepsilon}$
---
## SEIRD Model
### System of Equations
$$
\begin{cases}
\dot{S} = -\beta(1 - u)SI + \delta R \\
\dot{E} = \beta(1 - u)SI - \phi E \\
\dot{I} = \phi E - (\gamma + \varepsilon)I & \forall t \in (0, t^*] \\
\dot{R} = \gamma I - \delta R \\
\dot{D} = \varepsilon I
\end{cases}
$$
### Initial Conditions
$$
[S(0), E(0), I(0), R(0), D(0)]^T = [S_0, E_0, I_0, R_0, D_0]^T
$$
### Parameters
- Basic Reproduction Number: $\mathcal{R}_0 = \frac{\beta}{\gamma + \varepsilon + \phi}$
- Modified Reproduction Number: $\mathcal{R}_u = \frac{\beta(1 - u)}{\gamma + \varepsilon + \phi}$