The bivalent boosters were just 43% effective at preventing mild illness compared to receiving no vaccine in adults 49 and under, according to a US Centers for Disease Control and Prevention study published Tuesday. In those aged 50 to 64 years, comparative protection against symptomatic Covid was 28%, while the booster was just 22% protective in adults 65 and older, the study showed.
One month after a 30-µg booster dose of the Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine, neutralizing antibody titers against emerging Omicron sublineages increased 3.2- to 4.8-fold compared to the companies’ original COVID-19 vaccine Neutralizing antibody titers against Omicron sublineages BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1 increased 4.8- to 11.1-fold from pre-booster levels, following a 30-µg booster dose of the bivalent vaccine
同期，有研究指出
More adverse reactions following bivalent COVID-19 mRNA booster vaccine
https://www.healthdata.org/covid/covid-19-vaccine-efficacy-summary
注意最右边两个变种的数据，没有一个疫苗达到世卫和FDA的标准（50%防感染)
上表未包括双价疫苗。可以参考下面的数据
https://www.bloomberg.com/news/articles/2022-11-22/new-bivalent-covid-boosters-provide-some-protection-in-cdc-study-but-not-much?leadSource=uverify%20wall
The bivalent boosters were just 43% effective at preventing mild illness compared to receiving no vaccine in adults 49 and under, according to a US Centers for Disease Control and Prevention study published Tuesday. In those aged 50 to 64 years, comparative protection against symptomatic Covid was 28%, while the booster was just 22% protective in adults 65 and older, the study showed.
这个就是吃教授要引入中国给老年人打的疫苗。且不说价格，就那个22%保护率，谁能接受。
然而，疫苗公司坚持说双价疫苗提高了抗体多少倍。但没给出临床有效性数据。
https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-report-new-data-omicron-ba4ba5-adapted
One month after a 30-µg booster dose of the Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine, neutralizing antibody titers against emerging Omicron sublineages increased 3.2- to 4.8-fold compared to the companies’ original COVID-19 vaccine Neutralizing antibody titers against Omicron sublineages BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1 increased 4.8- to 11.1-fold from pre-booster levels, following a 30-µg booster dose of the bivalent vaccine同期，有研究指出
More adverse reactions following bivalent COVID-19 mRNA booster vaccinehttps://www.news-medical.net/news/20221113/More-adverse-reactions-following-bivalent-COVID-19-mRNA-booster-vaccine.aspx
轻症的阳性，根本不统计在内，无论是疫苗组和对照组都是如此。
疫苗诱导 IgM, IgG。
没有IgA，确切地说，没有诱导多少IgA。
能防感染当然好，但疫苗的目的都是防疾病。
这在FDA的 Guidance documents和疫苗的label (package insert)上都是很清楚的。防感染连这些疫苗临床三期的 Endpoint都不是。
https://blog.wenxuecity.com/myblog/52634/202211/18040.html
虽然个人仍相信当初P/M疫苗对delta virus还是有效用D, 但从未信过疫苗有效性能达80%--90%以上，这高得有点。。哈哈。
https://www.who.int/zh/news-room/feature-stories/detail/vaccine-efficacy-effectiveness-and-protection
注意最下面一行。
疫苗有效率如何计算？https://www.sohu.com/a/445040870_324765
国内外不少媒体也出现了疫苗有效率的计算方法，比如：
来源A：“对照组也就是安全组被感染人数作为分母，免疫组被感染人数作为分子求得百分比”
来源B：“随机对照试验纳入了43548人，平均分为两组。疫苗组有8人核酸确诊感染新冠，安慰剂对照组有162人核酸确诊感染新冠，两组相对差别 = (162-8) / 162 = 0.9506 = 95.06%”
来源C：“安慰剂组90人，疫苗组5人，每一组人数约1.5万。安慰剂组感染率为90/15000 = 0.6%，疫苗组粗感染率为5/15000 = 0.033%，疫苗的有效率计算式为 (0.6%-0.033%) / 6% = 94.5%”
这是由疫苗临床试验的设计目的确定的， 疫苗的作用是预防出现新冠症状的病人，即减少病人
用词是： Contract the disease. 中文网页是“染病”。
而下面一段说得很清楚：
中文版是这样的：
疫苗的保护作用和病毒传播COVID-19疫苗是应对大流行和预防重症和死亡的重要工具。就感染和传播而言，疫苗至少会提供一些保护，但保护作用没有在防止重症和死亡方面的作用大。还需要获得更多证据才能确定疫苗阻止感染和传播的程度。
To contract a disease means to catch or acquire an illness through the exposure to a contagious pathogen.
https://grammarist.com/eggcorns/contract-a-disease-or-contact-a-disease/
因为感染的临床难度非常大，而且没有什么必要。如果大家都是无症或轻症感染，根本也没有防疫和疫苗的必要了
我以前听过一耳朵讨论，如何证明感染？天天自己取核酸样品？取样准确度和subject compliance根本没法保证。记得NIH当时讲可能折中做 household infection的临床，但也没看到结果，不过我也没仔细跟踪，因为疫苗根本任务是为了防病，不是防感染。当然能防感染更好，但那是 bonus, 不是objective.
点开这个网站
https://www.worldometers.info/coronavirus/country/us/
点最右边projections栏目中的链接，可以查到该州与新冠相关的数据，包括医疗资源负荷
加州目前状况和未来预期
https://covid19.healthdata.org/united-states-of-america/california?view=cumulative-deaths&tab=trend
理论的前提。
这些都是 public record， 我没有看到过任何改变。
您说的代理商改口啥的，我就不知道什么出处了。要是虚假广告，是违法的，可以告他们。
https://bbs.wenxuecity.com/health/935730.html