Parameter
$d_{\mathit{ht}}^s$	Demand for vaccine $h$ during period $t$ in scenario‌$s$
	Variable
${\alpha }_{\mathit{rt}}^s$	If the vaccination center $r$ is set up during time $t$ under scenario‌ $s$, its value is 1; otherwise, it is 0.
${\beta }_{\mathit{tkij}}^s$	If the vehicle $k$ visits the points of $i$ and $j$ during period $t$ under scenario‌ $s$, its value is 1, and otherwise, it is 0.
${\mathrm{{\rm Y}}}_{\mathit{ktf}}^s$	If vehicle $k$ visits point $f$ during period $t$ under scenario‌ $s$, its value is 1; otherwise, it is 0.
${\partial }_{\mathit{ht}}^s$	Number of shortages of vaccine $h$ during period $t$ under scenario‌$s$
$U_{\mathit{hft}}$	Vaccine supply capacity by suppliers $f$ during period $t$
$V_{\mathit{ht}}$	Vaccine distribution capacity during period $t$
${U1}_{\mathit{stik}}$	Auxiliary variable for sub-tour elimination
${V1}_{\mathit{stik}}$	Auxiliary variable for sub-tour elimination