In this study, researchers developed several weakened forms of the SARS-CoV-2 virus by making changes to its genetic structure. These attenuated viruses were then considered as potential vaccines. The scientists tested these live-attenuated vaccine candidates on hamsters to evaluate how safe and effective they are.
Two candidates showed particularly encouraging results: when hamsters were given the vaccine through drops in the nose, they didn't get sick, and their immune systems responded in a way that shielded them from getting sick if they were later exposed to the actual harmful SARS-CoV-2 virus. These novel live-attenuated vaccine candidates offer significant advantages over other vaccine technologies and are promising for fighting the COVID-19 pandemic.