Volunteers must provide informed consent to participate in the trial. They will be asked to provide a nasopharyngeal swab and a blood sample at an initial screening visit and additional blood samples at specified time points after each vaccination and over the two years following the second vaccination. Scientists will examine blood samples in the laboratory to detect and quantify immune responses to SARS-CoV-2.
Investigators will closely monitor participant safety. They will call participants after each vaccination to discuss any symptoms and will provide participants with a diary to record symptoms and a thermometer for temperature readings.
If a participant is suspected to have COVID-19, the participant will be asked to provide a nasal swab for testing within 72 hours. If the test is positive for SARS-CoV-2 infection, the participant will be followed closely and referred for medical care if symptoms worsen. Participants will be asked to provide a daily assessment of symptoms through resolution and have saliva sampled periodically, so investigators can test for SARS-CoV-2 infection.
评价疫苗的效果主要有两个方面：1）自然感染人群的保护率；2）接种后的抗体上升的滴度水平是否达到保护的效价
1. 自然感染人群的保护率计算公式:
疫苗的保护率=(1-疫苗组感染率/对照组感染率)*100%
以昨天公布的Moderna公司公布的数据为例，接受了两剂疫苗的人群中只有11人出现新冠状病毒感染的症状，安慰剂组中有185个有症状的病例。该公司表示，这是94.1％的保护效果，
由于我们不知道接种和对照人数, 按一半一半计算(各为15000),
[1-(11/15000)/(185/15000)]*100%=94.1%
但这个保护率计算是有缺陷的，因为没有作全部3万人的病毒核酸检测，没有症状的感染者被忽略了，所以这个保护率是不够准确的。是有症状感染的新冠感染保护率，不是新冠感染的保护率.
2. 抗体上升的滴度水平
抗体的效价不如保护试验直接，因为没有人知道多少滴度的抗体能够起保护作用。唯一依据是和感染后病人的平均水平相当比较。轻症，重症病人产生的抗体也有差异。美国mRNA疫苗引发的抗体水平和感染后病人相当，而中国灭活病毒疫苗的引发抗体水平低于感染后病人。
参考文献：
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30843-4/fulltext
https://www.niaid.nih.gov/news-events/phase-3-clinical-trial-investigational-vaccine-covid-19-begins
Volunteers must provide informed consent to participate in the trial. They will be asked to provide a nasopharyngeal swab and a blood sample at an initial screening visit and additional blood samples at specified time points after each vaccination and over the two years following the second vaccination. Scientists will examine blood samples in the laboratory to detect and quantify immune responses to SARS-CoV-2.
Investigators will closely monitor participant safety. They will call participants after each vaccination to discuss any symptoms and will provide participants with a diary to record symptoms and a thermometer for temperature readings.
If a participant is suspected to have COVID-19, the participant will be asked to provide a nasal swab for testing within 72 hours. If the test is positive for SARS-CoV-2 infection, the participant will be followed closely and referred for medical care if symptoms worsen. Participants will be asked to provide a daily assessment of symptoms through resolution and have saliva sampled periodically, so investigators can test for SARS-CoV-2 infection.
https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-primary-efficacy-analysis-phase-3-cove-study
这违反伦理，也没有多少志愿者愿意
另外追踪两年主要看抗体的变化，间隔不会短。
在某种意义上讲，可以完全忽略无症状感染。
既然无症状，也就是说不死不伤不疼不痒，该干啥干啥，生活学习工作，喝酒吃肉跑步唱歌跳大绳，吃喝玩乐啥也不耽误，又有啥关系？
唯一的区别是检测结果。
退一步讲，随机双盲试验，疫苗组和对照组面临着完全同样的疫情环境。
对这类新闻, 个人通常不会仅凭篇报道或1个笼统数据, 希望能见到原文, 若有论文背景统计数据细节最好哈.