Changes in version 1.1.0 (2022-02-11) MAJOR CHANGES - Added impute_ref function to allow reference based imputation (copy reference). Reference based imputation usually is for sensitivity analysis purpose. Changes in version 1.0.0 (2021-10-11) MAJOR CHANGES - First public release of niaidMI that provides the implementation of Multiple Imputation with Markov Chain method in application to COVID-19 scale, NIAID-OS.