Monitoring Group Activity of Hamsters and Mice as a Novel Tool to Evaluate COVID-19 Progression, Convalescence, and rVSV-Delta G-Spike Vaccination Efficacy

The COVID-19 pandemic initiated a worldwide race toward the development of treatments and vaccines. Small animal models included the Syrian golden hamster and the K18-hACE2 mice infected with SARS-CoV-2 to display a disease state with some aspects of human COVID-19. A group activity of animals in their home cage continuously monitored by the HCMS100 (Home cage Monitoring System 100) was used as a sensitive marker of disease, successfully detecting morbidity symptoms of SARS-CoV-2 infection in hamsters and in K18-hACE2 mice. COVID-19 convalescent hamsters rechallenged with SARS-CoV-2 exhibited minor reduction in group activity compared to naive hamsters. To evaluate the rVSV-Delta G-spike vaccination efficacy against SARS-CoV-2, we used the HCMS100 to monitor the group activity of hamsters in their home cage. A single-dose rVSV-Delta G-spike vaccination of the immunized group showed a faster recovery than the nonimmunized infected hamsters, substantiating the efficacy of rVSV-Delta G-spike vaccine. HCMS100 offers nonintrusive, hands-free monitoring of a number of home cages of hamsters or mice modeling COVID-19.