Sequential immunization of macaques with rVSV-based vaccines for Lassa fever and Ebola virus suggests that rVSV platform does not have the pre-existing immunity issue.29 In this report, we pre-immunized IFNAR−/− C57/BL6 mice with rVSV vector expressing glycoprotein of HTNV 30 days before vaccination with rVSV-SFTSV/AH12-GP. This evidence concerns the gene ART4 and Lassa fever.