The Pfizer/BioNTech and Moderna coronavirus vaccines were both tested on animals.
Due to the emergency need and an accelerated rollout schedule, the Moderna vaccine was tested simultaneously on humans and animals. Researchers acknowledge that although parallel testing is not standard, nor the most effective, it is speedier. Vaccines usually undergo animal testing before the first human trials.
Pfizer tested its vaccine on mice and primates before moving onto trials with larger groups of human subjects.
Pfizer's vaccine received an emergency use authorization from the U.S. Food and Drug Administration on Dec. 11. Moderna's vaccine is expected to be authorized shortly, after being endorsed by an FDA advisory panel on Dec. 17.