Household transmission In China, human-to-human transmission of the COVID-19 virus is largely occurring in families. The Joint Mission received detailed information from the investigation of clusters and some household transmission studies, which are ongoing in a number of Provinces. Among 344 clusters involving 1308 cases (out of a total 1836 cases reported) in Guangdong Province and Sichuan Province, most clusters (78%-85%) have occurred in families. Household transmission studies are currently underway, but preliminary studies ongoing in Guangdong estimate the secondary attack rate in households ranges from 3-10%.
Contact Tracing China has a policy of meticulous case and contact identification for COVID-19. For example, in Wuhan more than 1800 teams of epidemiologists, with a minimum of 5 people/team, are tracing tens of thousands of contacts a day. Contact follow up is painstaking, with a high percentage of identified close contacts completing medical observation. Between 1% and 5% of contacts were subsequently laboratory confirmed cases of COVID-19, depending on location. For example: • As of 17 February, in Shenzhen City, among 2842 identified close contacts, 2842 (100%) were traced and 2240 (72%) have completed medical observation. Among the close contacts, 88 (2.8%) were found to be infected with COVID-19.
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As of 17 February, in Sichuan Province, among 25493 identified close contacts, 25347 (99%) were traced and 23178 (91%) have completed medical observation. Among the close contacts, 0.9% were found to be infected with COVID-19.
As of 20 February, in Guangdong Province, among 9939 identified close contacts, 9939 (100%) were traced and 7765 (78%) have completed medical observation. Among the close contacts, 479 (4.8%) were found to be infected with COVID-19.
Household transmission In China, human-to-human transmission of the COVID-19 virus is largely occurring in families. The Joint Mission received detailed information from the investigation of clusters and some household transmission studies, which are ongoing in a number of Provinces. Among 344 clusters involving 1308 cases (out of a total 1836 cases reported) in Guangdong Province and Sichuan Province, most clusters (78%-85%) have occurred in families. Household transmission studies are currently underway, but preliminary studies ongoing in Guangdong estimate the secondary attack rate in households ranges from 3-10%.
Contact Tracing China has a policy of meticulous case and contact identification for COVID-19. For example, in Wuhan more than 1800 teams of epidemiologists, with a minimum of 5 people/team, are tracing tens of thousands of contacts a day. Contact follow up is painstaking, with a high percentage of identified close contacts completing medical observation. Between 1% and 5% of contacts were subsequently laboratory confirmed cases of COVID-19, depending on location. For example: • As of 17 February, in Shenzhen City, among 2842 identified close contacts, 2842 (100%) were traced and 2240 (72%) have completed medical observation. Among the close contacts, 88 (2.8%) were found to be infected with COVID-19.
8
As of 17 February, in Sichuan Province, among 25493 identified close contacts, 25347 (99%) were traced and 23178 (91%) have completed medical observation. Among the close contacts, 0.9% were found to be infected with COVID-19. As of 20 February, in Guangdong Province, among 9939 identified close contacts, 9939 (100%) were traced and 7765 (78%) have completed medical observation. Among the close contacts, 479 (4.8%) were found to be infected with COVID-19.
https://www.who.int/docs/default-source/coronaviruse/who-china-joint-mission-on-covid-19-final-report.pdf
Household transmission
In China, human-to-human transmission of the COVID-19 virus is largely occurring in families. The Joint Mission received detailed information from the investigation of clusters and some household transmission studies, which are ongoing in a number of Provinces. Among 344 clusters involving 1308 cases (out of a total 1836 cases reported) in Guangdong Province and Sichuan Province, most clusters (78%-85%) have occurred in families. Household transmission studies are currently underway, but preliminary studies ongoing in Guangdong estimate the secondary attack rate in households ranges from 3-10%.
Contact Tracing
China has a policy of meticulous case and contact identification for COVID-19. For example, in Wuhan more than 1800 teams of epidemiologists, with a minimum of 5 people/team, are tracing tens of thousands of contacts a day. Contact follow up is painstaking, with a high percentage of identified close contacts completing medical observation. Between 1% and 5% of contacts were subsequently laboratory confirmed cases of COVID-19, depending on location. For example:
• As of 17 February, in Shenzhen City, among 2842 identified close contacts, 2842 (100%) were traced and 2240 (72%) have completed medical observation. Among the close contacts, 88 (2.8%) were found to be infected with COVID-19.
8
As of 17 February, in Sichuan Province, among 25493 identified close contacts, 25347 (99%) were traced and 23178 (91%) have completed medical observation. Among the close contacts, 0.9% were found to be infected with COVID-19.
As of 20 February, in Guangdong Province, among 9939 identified close contacts, 9939 (100%) were traced and 7765 (78%) have completed medical observation. Among the close contacts, 479 (4.8%) were found to be infected with COVID-19.
2. 口罩对于呼吸道疾病是双刃剑，呼吸不畅的人会更加用力呼吸，而大多数普通人戴口罩的方式根本不对，戴着口罩站在感染者附近未必比不戴口罩安全，拿下口罩如果没有正确洗手消毒液很危险，加上全民戴口罩造成医务人员和真正有病的人没有口罩用，是非常危险的。 这个世界如果没法一天生产出100亿个口罩，就不应该提倡全民戴口罩。再说，应勇戴着两口罩的时候，美国各级官员，从总统到地方卫生官员，你见过一个戴口罩的？
3. 对于疫情，网络其实起到了副作用，传播恐惧，散布谣言，2009的H1N1比现在的covid-19明显厉害，但那时网络信息还没有这么厉害，反而对抑制大众对恐慌是有好处的。
4. 美国情况根本就不是一月的武汉，CDC的guideline改了几次，现在医院已经扫了很多住院和之前呼吸道去世的人，发现的中招比例还是远没到值得恐慌的程度，我知道弯曲两间大医院，如果你去ER，发烧+呼吸道疾病或者有去过那些疫区，马上会安排做新冠检查（保险给保），CDC就算官僚，医院的医生护士可不傻，你要说我害怕，你给我测，那可能就得准备3500了。我从医院内部听到的情况就是没有隐瞒病情，有若干例未报道等待CDC确认的住院病人，但没有几百上千的隐瞒病例。接下去大概就是新加坡日本这种状态，不会消停，但也不会爆发，Keep Calm and Carry On。
5. 世界上稍微正常点的国家是不会搞彻底封城的，武汉重症的时候，正确的方式不是一边停工，停学，停春运，然后动用全国的医疗资源来救治武汉/湖北吗？在没有足够医疗资源和救治准备的时候把武汉封了，和三胖枪毙棒子有什么区别？把武汉/湖北人都当zombie，全中国人歧视武汉/湖北人的时候，大部分国际上的舆论/人并没有歧视中国人。中国正在经历的就是二次文革，人人自保，自私自利，爱国的前提是祖国爱的是自己。
那些人心理阴暗而已。哪有人血馒头吃哪边。
我来吧。
美国Flu每年感染比例5% 到 20%，这个肺炎不比Flu差，也用5% 到 20%的传染率。 假设WHO的死亡率是对的，3.4%，但心血管的10%； 重症率20%。再考虑到美国的特殊性，1.24亿有心血管病。美国3亿人口。
[table=347]
[td=112]单位数百万[td=70] 5% [td=77] 10% [td=88] 20%
3亿3.4%死亡率 0.51 1.02 2.04
1.24亿10%死亡率 0.62 1.24 2.48
3亿20%重症率 3 6 12
再考虑到现在已经3月份，每年Flu season是12月份到3月份，如果这个病温度高就下降，和Flu类似，那么只有1个月时间传播，就是1/4， 25%，把上面表调整一下。
[table=366]
[td=131]单位数百万3月份only[td=70] 5% [td=77] 10% [td=88] 20%
3亿3.4%死亡率 0.13 0.26 0.51
1.24亿10%死亡率 0.16 0.31 0.62
3亿20%重症率 0.75 1.50 3.00
大家觉得那种可能性最大，就挑数字吧。Flu每年死12000到60000.
同意楼主，看这个论坛，感觉大家有些过度紧张了。BTW H1N1是不是比这个厉害，持保留态度。
1. 从概率的角度来分析下这个事情，实际上没必要紧张，现在全美3亿人口，发现不到200个病例，也就说正常要碰到150万人才有可能碰到一个病例，即使考虑加州西雅图病例比较集中，翻10倍上去，也得碰了万把人才能碰到；简单比较病例数，西雅图现在的情况顶多也就是相当于1月初甚至12月底的武汉。
2. 大家比较怕的是无症状传播者，这个确实是最恐怖的，但是实际上也可以想象这种人的传播能力会比较弱，没有咳嗽把病菌从肺的下部带出来，光靠一般的呼吸能带出的病菌肯定会少很多；
3. 从美国的政治情况考虑，大家都在诟病CDC反应慢，检测数量少，但是可以相信的是，CDC的人比你我专业，他们也没有可能知情不报，里面具体的人如果碰到什么觉得不对的情况，还是有渠道发声而不会像国内那样被谣言。
4. 实际上折腾这么长时间了，对于这个病传染方式、治疗手段的理解肯定要比1月初的武汉强，医护人员也都不是傻子，反而他们比我们专业太多，还是值得相信的。
5. 再向后，天气开始热起来了，基本上可以相信的一个结论是病毒离开人体，在外界存活的时间随着气温而降低，所以随着气温的升高，病毒的传染性肯定是要下降的。
因此个人判断，除了伊朗以为，主要的痛苦过程差不多过去了，当然天气冷以后是不是会死灰复燃，这个就不知道了。