Your comment is very inaccurate actually and shows your did no research on the topic. Here's a bit of facts for you and does not include china's use of management vaccines
Phase 1 Trials: These initial trials focused on safety and dosage, involving a small number of healthy volunteers.
Phase 2 Trials: These expanded the study to more participants to further assess safety and start to evaluate effectiveness.
Phase 3 Trials: These were large-scale trials involving tens of thousands of participants to confirm efficacy and monitor for adverse effects.
For example, the Pfizer-BioNTech and Moderna COVID-19 vaccines each conducted Phase 3 trials with about 44,000 participants before receiving emergency use authorization and later full approval in Dec 2020 1.