可以去WHO网站看看专家的说法Vaccination protects you from getting seriously ill and dying from COVID-19. For the first fourteen days after getting a vaccination, you do not have significant levels of protection, then it increases gradually. For a single dose vaccine, immunity will generally occur two weeks after vaccination. For two-dose vaccines, both doses are needed to achieve the highest level of immunity possible.
While a COVID-19 vaccine will protect you from serious illness and death, we still don’t know the extent to which it keeps you from being infected and passing the virus on to others. To help keep others safe, continue to maintain at least a 1-metre distance from others, cover a cough or sneeze in your elbow, clean your hands frequently and wear a mask, particularly in enclosed, crowded or poorly ventilated spaces. Always follow guidance from local authorities based on the situation and risk where you live.
一个问题是
打了疫苗的人都不是老年人,很可能没打疫苗也是轻症。
逻辑上讲,只有过去被认为容易转为重症的人,比如老年人或者有基础疫病的,打了疫苗,感染了,轻症抗过去了,并且要大量例子,才能证明疫苗对防止重症有效。