https://zh.wikipedia.org/wiki/%E7%96%AB%E8%8B%97
疫苗是一種生物製品,可提供對特定傳染病的有效獲得性免疫[1] 。疫苗可用細菌、病毒、腫瘤細胞及代謝產物等製成的可使機體產生特異性免疫。而疫苗接種可使接受方獲得免疫力。
Nov. 18, 2020 輝瑞這樣說 ”Pfizer and BioNTech announced Wednesday that the efficacy portion of their Covid-19 vaccine trial has been completed, showing the vaccine to prevent 95% of cases of the disease.“
https://www.statnews.com/2020/11/18/pfizer-biontech-covid19-vaccine-fda-data/
新冠疫苗防傳染效果不好,所以不得已退而求其次擴展概念.