两项新的英国研究表明B.1.1.7变体比原来的更容易传播新冠肺炎(新型冠状病毒肺炎)变体;然而，它并不显得更致命或引起更严重的症状。
发表在《柳叶刀公共卫生》上的一项研究也报告说，在那些从以前的COVID感染中康复的人身上，B.1.1.7的再感染率较低。
正如预测的那样，疾病控制和预防中心现在报告说，B.1.1.7菌株是美国最主要的变体，在一些州占病例的30%以上。
但B.1.1.7并不是最近几个月出现的唯一新的、更具传染性的变体。根据疾病预防控制中心的说法，其他所谓的“令人担忧的变异体”包括首先在南非发现的变异体(第1.351节)和首先在巴西发现的变异体(第1节)。
B.1.351和P.1分别在南非和巴西流行，在美国这两个数字都很低。那么为什么英国的B.1.1.7版本会席卷全国呢?
专家表示，B.1.1.7有可能在美国传播，因为它比原始菌株更具传染性。B.1.1.7也可能在美国领先，在其他传染性更强的变体有机会站稳脚跟之前，有效地将其挤掉。
诺姆·加莱/盖蒂图像公司
2021年4月10日，纽约，人们在第五大道散步时戴着口罩。
“我们在全球范围内看到的是，更容易传播的变异将...战胜那些不容易传播的变体，”波士顿儿童医院首席创新官、美国广播公司新闻撰稿人约翰·布朗斯坦博士说。
根据布朗斯坦的说法，B.1.1.7能够迅速传播，是因为它在免疫接种普及之前就进入了该国。
关于B.1.1.7是否会战胜其他主要变异体，密歇根大学的流行病学家艾米丽·马丁博士说，“这取决于哪种变异体首先到达一群人，例如B.1.1.7是第一个在密歇根开始传播的，”
专家们仍然不确定为什么一些病毒变异体比其他病毒变异体更具传染性。
一个想法是，它们可以产生更大的病毒载量，这意味着它们可以在你的鼻子中产生更高水平的病毒，为病毒传播创造更大的机会。也有可能这些变异体更善于抓住或进入细胞，这意味着接触病毒的人更有可能被感染。
专家说，好消息是目前的疫苗和公众健康措施似乎对B.1.1.7有效
约翰·霍普金斯大学免疫学家兼环境健康与工程副教授吉吉·格伦瓦尔博士说:“我们可以开发更接近变异体的疫苗，但迄今为止，我们似乎已经有了有效的疫苗。”
汉娜·麦凯/路透社
人们把袖手旁观圣托马斯医院旁边的国家纪念墙作为纪念
“这些变种没有什么神奇的。所有大家都知道该怎么做的事情——戴口罩，通风好，距离等。——所有这些东西仍然有效，”格罗弗说。“这有点像接种疫苗的竞赛，因为这些变异体更容易传播，这削弱了接种疫苗的效果。”
布朗斯坦认为，在未来的几年里，专业的强化注射可能会为未来出现的任何新变体提供更好的保护。
布朗斯坦说:“随着我们让病毒进化，可能会有变异体可以逃避当前的疫苗，这就是助推器会有所帮助的地方。”
科学家们已经在测试助推器。但到目前为止，所有的证据表明，目前可用的疫苗可以预防乙型肝炎他们互相保护。
布朗斯坦说:“我认为我们应该在未来1-2年内看到美国的增长，但这将全部归结于住院和死亡率数据。”“我们还不知道助推器是基于B.1.1.7还是另一种变体。”
UK COVID variant more transmissible but may not be more deadly, new studies indicate
Two new British studies suggest thatthe B.1.1.7 variantis more transmissible than the originalCOVID-19variants; however, it does not appear to be more deadly or cause more severe symptoms.
One of the studies, published in The Lancet Public Health, also reported a low rate of reinfection with B.1.1.7 in those who have recovered from previous COVID infections.
As was predicted, the Centers for Disease Control and Prevention is now reporting the B.1.1.7 strain to be the most dominant variant in the U.S., accounting for over 30% of cases in some states.
But B.1.1.7 isn't the only new, more contagious variant to emerge in recent months. Other so-called "variants of concern" include a variant first identified in South Africa (B.1.351) and a variant first identified in Brazil (P.1), according to the CDC.
Both B.1.351 and P.1 have taken over in South Africa and Brazil, respectively, and both have been found in low numbers in the United States. So why is the B.1.1.7 U.K. variant sweeping the country?
Experts say it's possible that B.1.1.7 is spreading in the U.S. because it is more contagious than original strains. It's also likely that B.1.1.7 had a head-start in the U.S., effectively edging out the other more contagious variants before they had a chance to take hold.
"What we have seen across the globe is that more easily transmissible variants will ... outcompete those variants that don't spread as easily," said Dr. John Brownstein, the chief innovation officer at Boston Children's Hospital and an ABC News contributor.
According to Brownstein, B.1.1.7 was able to spread quickly because it entered the country before immunization became widespread.
In terms of whether B.1.1.7 will outcompete other major variants, epidemiologist Dr. Emily Martin, of the University of Michigan, said, "It depends on which variant reaches a group of people first, for example B.1.1.7 was the first to start spreading in Michigan,"
Experts still aren't sure why some viral variants are more contagious than others.
One idea is that they can create a more significant viral load, meaning they can produce higher levels of virus in your nose, creating a greater opportunity for the virus to spread. It's also possible that these variants are better at latching onto or getting into cells, meaning someone exposed to the virus is more likely to become infected.
The good news, experts say, is that current vaccines and publichealthmeasures appear to be effective against B.1.1.7.
"We can develop vaccines that are closer to the variants, but it seems that so far we have effective vaccines," said Dr. Gigi Gronvall, an immunologist and associate professor of environmental health and engineering at Johns Hopkins University.
"There is nothing magical about these variants. All the things that everyone knows how to do -- wearing masks, good ventilation, distance, etc. -- all these things are still effective," Gronvall said. "It is a bit of a race with vaccination, because these variants are more transmissible, which is blunting the effect of the vaccination."
According to Brownstein, it's possible that in the years ahead, specialized booster shots may offer even better protection against any new variants that emerge in the future.
"As we let viruses evolve, there may be variants that can evade current vaccines, which is where boosters will be helpful," Brownstein said.
Scientists are already testing booster shots. But so far, all evidence indicates that currently available vaccines protect against the B.1.1.7 likethey protect against the others.
"I think we should see a booster in the U.S. in the next 1-2 years, but this will all come down to hospitalization and mortality data," Brownstein said. "We don't know yet if the booster will be based on B.1.1.7 or another variant."
