疫情的阴云还未散去，前不久又在世界各地发现了多个新冠病毒新变种，其中以在英国、南非和巴西出现的几个变种威力最强。这些变种有多危险？最近陆续上市的新冠疫苗对这些变种是否有效？来看看专家怎么说。图片来源：路透社现阶段涌现出的新冠病毒新变种比疫情初期的毒株更具传染性。New variants of coronavirus are emerging that are more infectious than the original one that started the pandemic.科学家正迫切地研究这些变种毒株，以了解它们的威胁性有多大。Scientists are urgently studying these mutated versions to understand what threat they pose.专家们目前最关注的是以下几种新冠病毒新变种：Experts' concerns currently focus on a small number of new variants of coronavirus:出现在英国的变种：在英国大部分地区蔓延，并传播到50多个其他国家A UK variant that has become dominant in much of Britain and has spread to more than 50 other countries出现在南非的变种：除南非以外，在包括英国在内的至少20个国家也发现了这一变种A South Africa variant that has also been found in at least 20 other countries, including the UK巴西新出现的变种A new variant from Brazil出现新变种，这是意料之中的事，因为所有病毒在复制过程中都会变异，这样才有利于传播和繁殖。It's not unexpected that new variants have developed - all viruses mutate as they make new copies of themselves to spread and thrive.当前在传播过程中的新冠病毒变种版本多达数千甚至数万个。There are many thousands of different versions, or variants, of Covid circulating.大部分变异都是无关紧要的。其中有少数变异甚至不利于病毒的生存。但是有些变异则会让病毒更具传染性或威胁力。Most of these differences are inconsequential. A few can even be harmful to the virus's survival. But some can make it more infectious or threatening.图片来源：路透社新冠病毒新变种的威胁力有多大？有人怀疑，英国、南非和巴西出现的变种可能比早期毒株的传染性要强得多。It's suspected that the UK, South Africa and Brazil variants could be much more contagious or easy to catch than earlier versions.这三种毒株的纤突蛋白都发生了变异，纤突蛋白是病毒附着到人体细胞的部分。All three have undergone changes to their spike protein - this is the part of the virus which attaches to human cells.因此，这些变种似乎更容易感染人体细胞和传播。As a result, these variants seem to be better at infecting cells and spreading.专家认为，9月份在英国发现的“肯特”变种传染性可能要高出70%，不过英格兰公共卫生署最近的研究认为该变种的传染性比原毒株高出30%到50%。Experts think the UK or "Kent" strain emerged in September and may be up to 70% more transmissible or infectious, although latest research by Public Health England puts it between 30% and 50%.10月份在南非发现的变种在纤突蛋白上发生的变异可能比英国变种更厉害。The South Africa variant emerged in October, and it has more potentially important changes in the spike protein than the UK variant.南非的变种毒株的纤突蛋白发生的其中一处变异和英国变种相同，另外还有两处变异，科学家认为可能会干扰疫苗的有效性。其中一处干扰疫苗的变异可能会帮助病毒躲避人体免疫系统中的部分抗体。It has one of the same mutations as the UK one, plus two more that scientists think may interfere more with vaccine effectiveness. One of these may help the virus evade parts of the immune system called antibodies.最近在从巴西抵达日本的四名旅客身上检测到的变种毒株是在去年7月份在巴西出现的。这一变种的纤突蛋白有三处关键变异和南非出现的变种相似。The Brazil variant emerged in July and was recently detected in four travellers arriving in Japan from Brazil. It has three key mutations in the spike protein that make it similar to the South Africa one.图片来源：路透社疫苗对新变种有效吗？当前的疫苗是针对早期毒株设计的，但是科学家相信它们对新变种也有效，不过可能有效性会打折扣。The current vaccines were designed around earlier variants, but scientists are confident that they should still work against the new ones, although perhaps not quite as well.实验室正在开展研究以确认疫苗是否对新变种有效。Lab studies are underway to check this.疫苗会训练人体攻击病毒的几个部位，不只是攻击纤突蛋白的特定部位。Vaccines train the body to attack several parts of the virus, however, not just these sections of the spike protein.未来的变种可能还会发生更大的变异。Variants could emerge in the future that are more different again.专家表示，即使最坏的情况发生了，人类也可以重新设计和调整疫苗，以更好地匹配新变种，如果有必要的话，数周或数月内就可完成。Even in the worst case scenario, the vaccines could be redesigned and tweaked to be a better match - in a matter of weeks or months, if necessary, say experts.流感疫苗每年都要注射以应对流感病毒在传播过程中的变异，新冠疫苗可能也会如此。As with flu vaccines, where a new shot is given each year to account for any changes in circulating flu viruses, something similar could happen for coronavirus.新变种是否更危险？目前没有证据表明任何一个变种会导致更严重的疾病。There is currently no evidence to suggest that any of them cause more serious illness.勤洗手、同他人保持距离和佩戴口罩等措施仍然有助于防止被感染，但因为新变种更容易传播，所以我们应当格外警惕。Measures such as washing your hands, keeping your distance from other people and wearing a face covering will still help prevent infections, and because the new variants spread more easily it is important to be extra vigilant.