Moderna's vaccine was only tested on mice and macaques. It was not tested on ferrets.
The vaccine from Moderna relies on messenger RNA (mRNA) which contains a genetic code that trains the immune system to recognize the spike protein on the surface of the virus to generate an immune response. University of Pennsylvania professor of medicine Dr. Drew Weissman, who has been studying mRNA and mRNA vaccines for decades, told Associated Press that the "Moderna vaccine does not cause dangerous inflammation to animals." The Moderna vaccine passed the animal trial.