This R package is an implementation of extended state-space SIR models developed by Song Lab at UM school of Public Health. There are several functions available by 1) including a time-varying transmission modifier, 2) adding a time-dependent quarantine compartment, 3) adding a time-dependent antibody-immunization compartment. The package require the installation of JAGS-4.x.y.exe and of other R packages: rjags, chron, gtools.