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Hey, guys. I'm Dr. Mike Hansen and welcome to another video.
大家好。我是迈克·汉森博士，欢迎收看我们的视频。
Recently, the Delta variant of COVID-19, a.k.a B.1.617.2, has been spreading across the globe.
最近，新冠肺炎变异毒株德尔塔已在全球蔓延。
Is it more contagious?
它的传染性更强吗？
Will the vaccines work against it?
疫苗对它有效吗？
Is it a deadlier disease with worse symptoms?
它是一种症状更严重的致命疾病吗？
I'm going to get to these questions in a little bit. But first, a quick update on COVID.
我一会儿会回答这些问题。我们先来快速了解一下新冠肺炎的最新情况。
The U.S. has over 33 million confirmed cases and more than 601,000 deaths.
美国确诊病例目前已超过3300万例，死亡病例超过60.1万例。
Worldwide, that's about 180 million cases, and close to 4 million deaths.
在全球范围内，确诊病例大约为1.8亿例，死亡病例近400万例。
According to the CDC, almost 150 million Americans have been fully vaccinated, that's about 45 percent of the population.
根据美国疾病控制与预防中心的数据，已有近1.5亿美国人全面接种了疫苗，这一数字约占总人口的45%。
The Delta variant first emerged in India, and then it made its way to England to become the dominant strain there.
德尔塔变异毒株首先出现在印度，然后来到了英国，并成为了那里的主要毒株。
Is the Delta variant more pathogenic, meaning is it more likely to cause worse disease?
德尔塔变异毒株是否更具有致病性，也就是说，它是否更有可能导致更严重的疾病呢？
Yes. In a study done in Scotland, which was published in the Lancet,
是的。根据一项发表在《柳叶刀》上的苏格兰研究显示，
researchers showed that the risk of being hospitalized with the Delta variant is double that of the Alpha variant.
因德尔塔变异毒株住院的风险，是阿尔法变异毒株的两倍。
Recently, the Delta variant has made its way to the U.S., where already constitutes 10 percent of COVID cases.
最近，德尔塔变异毒株已传入美国，在新冠肺炎总病例中占比达到了10%。
However, that figure is doubling every two weeks, and it's only a matter of time before it becomes a dominant strain.
但是这个数字每两周就会翻一番，因此成为主要毒株只是时间问题。
Right now, in the midwest, it makes up about 25 percent of cases in Colorado, Montana, North and South Dakota, Utah and Wyoming.
现在，该毒株约占科罗拉多州、蒙大拿州、北达科他州、南达科他州、犹他州和中西部怀俄明州的病例的25%。
Now in a study done in the UK, from May 20th to June 7th,
根据5月20日至6月7日在英国进行的一项研究，
the researchers led by Stephen Riley, they looked at their data which suggested that the Delta variant is about 60 more transmissible than the Alpha.
由史蒂文·莱利领导的研究人员查看了他们的数据，结果表明，德尔塔变异毒株的传播率比阿尔法变异毒株高约60%。
The research team showed that with the Delta variant, there was a doubling time of 11 days in an estimated R (or Reproductive Number) of 1.44.
此外，该研究团队表示，德尔塔变异毒株的倍增时间为11天，基本再生数为1.44。
And those younger than age 50 were 2.5 times more likely to be infected compared to older people.
50岁以下人群被感染的可能性是50岁以上人群的2.5倍。
Another study looked at whether vaccines, monoclonal antibodies, or antibodies derived from COVID-19 survivors, could neutralize the Delta variants.
另一项研究则关注了疫苗、单克隆抗体或来自COVID-19幸存者的抗体，是否可以中和德尔塔变异毒株。
Here are some of the takeaways from that study.
以下是该研究得出的一些结论。
For one, the data showed that the Delta's variant affinity for the ACE2 receptor was slightly better compared with the original strain.
其一，德尔塔变异毒株对ACE2受体的亲和力略好于原始毒株。
One of the Delta's mutations is in its receptor binding domain, and that's what allows for this.
德尔塔变异毒株在其受体结合区中的突变之一，是造成这一结果的原因。
This virus uses spike protein to bind to the ace2 receptor in the body. It's the key and lock analogy.
该病毒可通过表面的刺突蛋白与人体内的ACE2受体结合。这是一种“锁与钥匙的模型”。
The virus then fuses with the cell membrane, this process relies on cleavage,
然后病毒会与细胞膜融合，这个过程依赖于分裂，
meaning enzymes on the cell membranes that cut that spike protein at two different sites, which triggers the cell to then engulf this virus.
意思是说细胞膜上的酶在两个不同的位点切割刺突蛋白，触发细胞吞噬病毒。
It's the turning of the deadbolt if you will.
这就相当于转动门栓了。
Well, guess what the Delta variant is also better at doing.
猜猜德尔塔变异毒株还擅长做些什么。
There's a second Delta mutation at one of the cleavage sites, better cleavage, better reproduction.
在其中一个位点上，会发生第二个德尔塔突变，分裂越好，繁殖越好。
Another takeaway from the study is that the authors concluded that
关于这项研究，作者得出的另一个结论是，
neutralization of both viruses is reduced when compared with the original strain, but there's no evidence of widespread antibody escape.
与最初的毒株相比，抗体对这两种变异毒株的中和作用是有所降低的，但并没有证据表明这是免疫逃逸。
They said the data did suggest that those previously infected with COVID may be more susceptible to re-infection by the new Delta variant.
研究人员称，数据确实表明，之前感染过新冠肺炎的人，可能更容易再次被新的德尔塔变异毒株感染。
Also it looks like monoclonal antibody treatments are ineffective at treating the Delta variant.
此外，单克隆抗体治疗看起来对德尔塔变异毒株也没有什么效果。
The big concern is vaccine escape meaning that the current vaccines will become far less effective as the virus evolves.
目前最大的担忧是“免疫逃逸”，这意味着随着病毒的进化，当前的疫苗将会变得不那么有效了。
So far it hasn't happened, but eventually we'll need new vaccines for the variants, likely a yearly thing.
虽然目前还没有定论，但我们最终还是需要针对这些变异毒株的新型疫苗，可能每年都需要注射一次。
The good news is that these vaccines are still protective against the Delta variant.
好消息是，新冠肺炎疫苗对德尔塔变异毒株仍有一定的预防作用。
According to research released by Public Health England, for the Pfizer vaccine, after both doses,
根据英国公共卫生部发布的研究显示，在两次接种辉瑞疫苗后，
it was 88 effective in preventing symptomatic disease and 96 effective at preventing hospitalization.
预防症状性疾病的有效率为88%，预防入院治疗的有效率为96%。
For the Oxford-AstraZeneca vaccine, if they had both shots, it was 92 effective at preventing hospitalization.
如果两次接种牛津-阿斯利康疫苗，那么预防入院治疗的有效率为92%。
If you only get one shot of either one of these vaccines, the effectiveness is pretty low, it's around 30 to 40 percent.
如果这两种新冠疫苗你只接种过一次，则其有效性非常低，约为30%至40%。
So more studies will soon be available when it comes to the Moderna and the Johnson & Johnson vaccines.
而关于Moderna疫苗和强生疫苗的研究结果，也将马上公布。
There's also talk about this delta variant having new symptoms and possibly more severe symptoms.
也有观点认为，德尔塔变异毒株会引发新的、更严重的症状。
So Tim Spector, who's a professor of genetic epidemiology at King's College in London, he runs the Zoe COVID symptoms study.
伦敦国王学院遗传流行病学教授蒂姆·斯佩克特，负责的就是研究Zoe新冠病毒的症状。
This is an ongoing UK-based study where people can enter their symptoms on an app which then gets analyzed by the researchers.
这是一项正在进行的英国研究，人们可以在一款应用程序上输入自己的症状，然后由研究人员进行分析。
From this study, he noted that COVID is now acting differently, it's more like a bad cold especially in the younger population.
蒂姆·斯佩克特指出，根据这项研究，他发现新冠病毒现在的症状已经有所不同了，表现得更像是重感冒，尤其是在年轻人群当中。
The No.1 symptom: being headache, and the other symptoms including sore throat, runny nose and fever.
排名第一的症状是头痛，其他症状还包括咽喉痛、流鼻涕和发烧。
