Vaccine candidates normally have to go through animal testing first before they go through the three phases of clinical trials in human beings. Among the 44 candidate vaccines that researchers are working on, only two are so far in Phase 1 clinical trials in humans.
The first vaccine to enter Phase 1 clinical trials, investigating safety and efficacy in humans is -the RNA vaccine developed by Moderna. The vaccine is being tested on volunteers at the Kaiser Health Research Institute in Seattle.
The other vaccine candidate currently in Phase 1 trials is Ad5-nCoV by Cansino Biologics Inc, based in Tianjin, China. The clinical trial on 108 subjects wiill take place at Tongji Hospital in Wuhan, where the COVID-19 pandemic began.
According to Global Alliance for Vaccines or GAVI, unlike the Moderna vaccine, this one has already been tested on animals. It has shown to be safe and triggers an immune response.