Usually, these clinical trials run one after another, with time given for the data on how safe, effective and stable the vaccine is to be looked at, and to make a decision about whether the trial should progress to the next stage.
通常,這些臨床試驗會陸續進行,有時間看疫苗的安全性、有效性和穩定性的數據,並決定是否進入下一階段的試驗。