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[搬运工]奥斯陆报告

拍老师 拍照稀烂的焦虑怪 2022-01-03
大家好~
今天咱继续走点含焦量高的东西吧

话说,前段时间咱提到过一嘴,
挪威奥斯陆圣诞晚宴超级传播事件,
各位应该还有印象吧?
没印象的话请复习这里:[变异毒株]2021年12月4日,Omicron最新情况汇总
没想到的是,
奥斯陆市政府和奥斯陆大学非常难得地高效了一发,
就在昨天晚上,
他们把这次事件的case report赶出来了,
从出事儿到见刊统共不到半个月,
这效率,放在北欧,妥妥的奇迹……
所以这玩意儿基本算是Omicron大流行以来,
第一份详细的聚集性感染事件案例报告,
价值很高,
(含焦量也很高)
咱还是详细品鉴品鉴吧。

——请看:

标题:

Omicron变异株引起的爆发,挪威,2021年11月到12月




背景介绍:

In late November 2021, an outbreak of Omicron SARSCoV-2 following a Christmas party with 117 attendees was detected in Oslo, Norway. We observed an attack rate of 74% and most cases developed symptoms. As at 13 December, none have been hospitalised. Most participants were 30–50 years old. Ninety-six percent of them were fully vaccinated. These findings corroborate reports that the Omicron variant may be more transmissible, and that vaccination may be less effective in preventing infection compared with Delta.

翻译成人话:

2021 年 11 月26日,挪威奥斯陆,

同一家公司的117 名员工举行了一次圣诞派对,

其中一名员工于11月24日从开普敦返回奥斯陆,

并感染了Omicron变异株,

由此引发了一次新冠病毒聚集性爆发。


对于这一事件,奥斯陆大学观察到:

- 罹患率74%

- 绝大多数病例出现症状;

- 截至12月13日暂时无人住院;

- 大多数参与者年龄在30-50岁之间;

- 其中 96%已完全接种疫苗。


奥斯陆大学表示:

以上发现证实了Omicron变异株可能传染性更强,

并且与Delta变异株相比,

疫苗接种在防Omicron感染方面的效果可能较差。

当然,以上情况我们已经大致知道了。
还是看下面的细节吧。



事发现场:

The closed event was held in a separate room (ca145 m2) in a restaurant in Oslo from 18:00 to 22:30, after which the venue was opened to the public from 22:30 to 03:00. A pre-party had been arranged for the Christmas party attendees at a separate venue, after which they were transported by private buses to the restaurant. Although there were no restrictions in place for events at the time in Norway, all attendees of the party were reported to be fully vaccinated and had been asked by the organiser to perform a rapid antigen self-test. For other guests visiting the venue and employees working at the restaurant, there were no requirements for vaccination, COVID-19 testing, facemask use or COVID certificate, and a guest list was not maintained. Attendees of the party mingled at the venue before and after dinner, following which the bar and dance area was opened to the public.


After detection of the outbreak on 30 November, all attendees at the party were requested by the municipality doctor in Oslo to self-quarantine at home for 10 days and to immediately take a PCR test. Those who tested positive were required to remain in isolation for at least 7 days [3]. In addition, a public message was released on 1 December asking anyone who had been at the venue from 22:30 on 26 November to 03:00 on 27 November to get tested by PCR as soon as possible, regardless of symptoms.

翻译成人话:

圣诞爬梯在奥斯陆某餐厅举行;

餐厅给参加者安排了一个大包(约145 平米);

时间是.5晚上6点到10点半左右;

爬梯散场之后,这个大包继续向公众开放直到凌晨3点;

这个圣诞爬梯其实还是二次会……

参加者已经在其他地方搞过一次会了,

然后才乘坐私人大巴到餐厅。

爬梯组织者要求所有参加者都需要疫苗并事先进行检测;

但同一场地其他客人和餐厅员工,

则没有接种/检测/戴口罩/提供接种证书等方面的要求,

也没有保留名单。

爬梯参与者在餐前和餐后都在该餐厅的其他区域活动,

并且随后该餐厅的酒吧和舞蹈区也向公众开放。

总结总结:
  • 高危暴露场景=145平米/117人;

  • 高危暴露时间=4.5小时;

  • 高危暴露方式=吃饭/爬梯/社交/跳舞/喝酒;

  • 同一家餐厅的工作人员/其他客人其实也应该算是密接……




病例构成和临床信息:

In total, 111 out of 117 attendees (95%) participated in the interviews. Respondents had an average age of 39 years (SD: 9.2; median: 38; range: 26–68) and 48 (43%) of them were women. Most respondents (n = 107; 96%) were fully vaccinated. Eighty-nine percent of the respondents (n = 99) had received two doses of mRNA vaccines. None reported having received a booster dose. All respondents reported having a negative rapid antigen self-test taken at home or PCR within 1–2 days before attending the event. Eight (7%) respondents had previously had COVID-19, but none in the previous 4 months, according to information gathered through the interviews.


Of the 111 respondents, 66 (59%) were confirmed cases (26 based on WGS and 40 based on PCR VOC screening) and 15 (14%) were probable cases (PCR-positive only). One PCR-positive attendee was confirmed to be infected with SARS-CoV-2 Delta variant (Pango lineage B.1.617.2), and subsequently excluded from further analysis. The total attack rate for the Omicron variant was 74% (81/110) (Figure). The cases had an average age of 38 years (SD: 8.6; median 36, range: 26–61) and 35 (43%) were women. The remaining 29 attendees did not have a positive PCR result by 13 December 2021.

翻译成人话:

总共117人参加11月26日的圣诞爬梯,

其中有111人 (95%) 接受了奥斯陆大学事后的随访。

受访者平均年龄为39岁(标准差:9.2;中位数:38;散布:26-68);

其中 48 人(43%)是女性。

96%受访者(n = 107)已完全接种;

89%受访者 (n = 99) 接受了两剂mRNA疫苗;

没有人接种过第三针。

所有受访者都在参加活动前1-2天接受过抗原快筛或PCR检测;

7%受访者(n=8)是既往感染者,但既往感染史发生在圣诞爬梯4个月之前。


在111名受访者中,

66 例(59%)为实锤Omicron病例(26例基于全基因组测序结果,40例基于PCR变异株筛查结果);

15 例(14%)为疑似Omicron病例(仅PCR 阳性)。

另有一名PCR阳性者被确认感染Delta,已被本研究排除在外;

Omicron变异株的总罹患率为74% (81/110)。


以上病例的平均年龄为 38 岁(SD:8.6;中位数为 36,范围:26-61);

其中35例(43%)为女性。

截止2021年12月13日,还有29名参与者PCR结果未呈阳性。

划重点啊:
  • 罹患率74%;

  • 中位数年龄38岁(其中感染者更是只有36岁);

  • 接种率96%(其中感染者接种率98%)。




重点来了

Assuming exposure occurred at the party, the incubation period for symptomatic cases ranged from 0 to 8 days with a median of 3 days (interquartile range: 3−4).


One case was asymptomatic and 74 (91%) reported at least three symptoms. Among the 81 cases, the most common symptoms were cough (83%), followed by runny/stuffy nose (78%), fatigue/lethargy (74%), sore throat (72%), headache (68%) and fever (54%) (Table). When asked to grade the severity of symptoms on ascale from 1 (no symptoms) to 5 (significant symptoms), 42% (33/79) reported level 3 symptoms, whereas 11% (9/79) reported level 4 symptoms. None of the cases required hospitalisation up to 13 December 2021. Duration of symptoms cannot be estimated accurately since 62 (78%) of the 80 symptomatic cases were still experiencing symptoms at the time of the interviews.


Seven cases reported symptoms consistent with COVID-19 within 2 weeks prior the party, with less than five reporting onset more than 1 week before the party.

翻译成人话:

如果假设高危暴露发生在本次圣诞爬梯期间的话,

那么对于有症状的病例,潜伏期为0至8天,


中位数潜伏期为3天(四分位距:3-4)。


所有感染者中只有1例无症状,另有74例 (91%) 报告了至少三种症状。


在81位感染者中,最常见的症状是咳嗽(83%),其次是流鼻涕/鼻塞(78%)、疲劳/嗜睡(74%)、咽痛(72%)、头痛(68%)、发烧( 54%)。


受访者自行报告的症状严重程度分级(1-5级)如下:

3级症状42% (33/79) ;

4级症状 11% (9/79) 。


截至2021年12月13日,所有病例均无需住院。


由于 80 例有症状病例中有62例(78%)在受访时时仍有症状,所以无法确定症状持续时间。


另外7位病例在参加爬梯前2周内出现过符合新冠病毒感染症病征的症状,还有不到5位病例在参加爬梯前1周以上出现过上述症状。

不知道各位读到这一段感觉咋样,
反正咱已经完全焦麻了……
甚至比一开始知道罹患率74%还更焦虑。

中位数潜伏期3天是尼玛什么概念???

——请各位看看中疾控的这张PPT(可能需要点开大图):

↑ 如上,

各位请仔细瞅瞅左下角的图C,

潜伏期曲线和代际间隔曲线,

这两者的波形是不是几乎一毛一样?

这不是啥巧合,而是有内在联系。


或者说,对于新冠病毒这张病原体,

潜伏期和代际间隔是正相关的。

一般而言,潜伏期中位数越长,

则代际间隔中位数越长。

比如说潜伏期中位数4天,

则代际间隔中位数差不多是3天,

如果潜伏期中位数变成3天,

则代际间隔中位数就要变成两天左右……

道理就这么简单。


而代际间隔,

是决定病原体倍增速度最主要的因素,

没有之一。


至于为啥潜伏期跟代际间隔相关?

很简单,

潜伏期的定义是从感染到出现症状的时间间隔;

然而出现症状的时机又和病毒载量相关,

病毒载量越高,则症状越明显。


再然后,病毒载量同时又和传染周期相关,

只有病毒载量高到一定程度,

病例才开始具有传染性。


所以根据新冠病毒感染症的传染周期,

一般在出现症状前两天左右,

病例开始具有传染性。


同时,代际间隔的定义是:

【原发病例感染病毒到续发病例感染病毒的时间间隔】

而根据上述传染周期,

只有表现出传染性的原发病例,

才能感染续发病例。

这就是为啥两条曲线长相如此接近,

也就是为啥潜伏期越短,则代际间隔越短。


对于国内而言,

一切的非药物式干预策略,

都需要根据病毒的传播动力学参数来科学设计,

这样才能实现精准防控。

而代际间隔,正是病毒播动力学参数最关键个。

代际间隔一变,

整个管控策略都有可能需要跟着调整,


举个反面例子啊,

就说今年5月份之前的越南吧,

搞清零搞得何其风光?

曾经35天摁平Alpha引发的大范围社区爆发,

这本事,任谁都挑不出一点毛病。

然而Delta一来,

代际间隔从5天缩短到3天,

越南顿时就被搞懵了逼……

(顺便自吹一句,咱在5月初就通过分析越南安沛省流调记录得出了Delta代际间隔≈3天的结论,比国内主流渠道也就早了一个月左右吧,嘿嘿~)


——咱5月5日发的知乎专栏文,请品鉴:

总之,当初越南第一波安沛省隔离酒店事故引起社区爆发,

连带引爆了三个院感事件,搞了越南满头包;

紧接着第二波北江省/北宁省工业区大爆发,

已然逼近了越南管控能力的极限……

前后蔓延快两个月,中招上万人,

终于勉强摁平;

结果还没来得及喘口气,

胡志明/平阳省一波大的,

(再配合人奸作祟)

直接断绝了越南清零的最后希望~


现在回头来看,越南当时问题出在哪儿?

除了胡志明的关键位置出了人奸之外,

最明显的毛病就是他们当初那套三代流调两代隔离的打法,

过分偏重居家隔离,

而忽视了检测密度和时效。

对付Alpha还比较管用,

但碰上代际间隔缩短后的Delta,

刚好会在检测的间隙漏掉传播链,

最后形成流调追不上、隔离堵不住的死局……

在北江省/北宁省那阵,
还勉强靠着吃喝拉撒不离工厂的大范围隔离来强行稳住阵脚,
但这一套拿到胡志明继续用,
就是死字写脸上。

作为对比,
同期的广州社区爆发,
开局其实闹得比较被动,
但后期及时调整,
通过搞大范围集中隔离和多轮次普筛,
最后有惊无险挽回了局面。

另外同期还发生了土澳墨尔本社区爆发,
当时维州靠着大范围低烈度闪断封城和加大流调力度,
也算是针对到了Delta代际间隔短的这个特征。

所以,回到当前啊,
如果Omicron的三天中位数潜伏期不是特例,而是它的内生属性;
如果它的代际间隔真的会跟着潜伏期一起缩短,
那就可能是本次疫情我们将面临的最大条的挑战。
(甚至比七成多的罹患率更加大条)



最后,毒力(virulence)/致病性(pathogenicity)也值得提一嘴,
奥斯陆报告这81位感染者里面,
80位都有症状;
其中91%(74例)有三种以上症状;
其中78%(62例)的症状持续了8天或以上。

——具体请品鉴:


这尼玛,
对于中位数年龄36岁且打完疫苗的人群
这致病性难道不算爆了表?
说好的MILD呢???



最后,总结总结吧:

  • 74%罹患率;

  • 3天中位数潜伏期;

  • 99%有症状。


不知道各位怎么想,
反正咱已经被吓尿了~


本报告原文见这里:


Outbreak caused by the SARS-CoV-2 Omicron variant in Norway, November to December 2021

Brandal, Lin T. and MacDonald, Emily and Veneti, Lamprini and Ravlo, Tine and Lange, Heidi and Naseer, Umaer and Feruglio, Siri and Bragstad, Karoline and Hungnes, Olav and Ødeskaug, Liz E. and Hagen, Frode and Hanch-Hansen, Kristian E. and Lind, Andreas and Watle, Sara Viksmoen and Taxt, Arne M. and Johansen, Mia and Vold, Line and Aavitsland, Preben and Nygård, Karin and Madslien, Elisabeth H., Eurosurveillance, 26, 2101147 (2021), https://doi.org/10.2807/1560-7917.ES.2021.26.50.2101147


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