大於 94% 的疫苗有效率是什麽意思？

你跟老百姓說 94% 有效，老百姓認為是這樣的：

30000 人， 15000 接苗，15000 不接苗，都給病毒，不接苗的 100% 感染，接苗的 94% 不感染。

實際呢，自然感染，接苗的 15000 裏感染了 11 個，不接的 185 個， (1-11/185)*100 = 94.1% 有效！

此外，確診的 30 例重症患者，全在不接苗的裏邊兒。

 

下麵截錄的是 Moderna 的：來自：https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-primary-efficacy-analysis-phase-3-cove-study

The Phase 3 study, known as the COVE study, enrolled more than 30,000 participants in the U.S. and is being conducted in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), and the Biomedical Advanced Research and Development Authority (BARDA), part of the Office of the Assistant Secretary for Preparedness and Response at the U.S. Department of Health and Human Services.

The primary endpoint of the Phase 3 COVE study is based on the analysis of COVID-19 cases confirmed and adjudicated starting two weeks following the second dose of vaccine. Vaccine efficacy has been demonstrated at the first interim analysis with a total of 95 cases based on the pre-specified success criterion on efficacy. Today's primary analysis was based on 196 cases, of which 185 cases of COVID-19 were observed in the placebo group versus 11 cases observed in the mRNA-1273 group, resulting in a point estimate of vaccine efficacy of 94.1%. A secondary endpoint analyzed severe cases of COVID-19 and included 30 severe cases (as defined in the study protocol) in this analysis. All 30 cases occurred in the placebo group and none in the mRNA-1273 vaccinated group. There was one COVID-19-related death in the study to date, which occurred in the placebo group.