The heavily mutated new coronavirus variant was in Europe several days earlier than previously known, health officials said Tuesday, and the number of countries where it has been found increased to at least 20, raising questions about whether the pandemic is about to surge once again.

卫生官员周二表示，高度变异的新冠病毒变异株在欧洲出现的时间比此前已知的还要早上数日，而发现它的国家增加到至少20个，这引发了人们对于疫情是否会再次暴发的疑问。

The Netherlands’ National Institute for Public Health and the Environment said that samples taken on Nov. 19 and Nov. 23 — before the Nov. 24 announcement of Omicron’s existence — tested positive for the variant. Health officials have notified the two infected people and are doing contact tracing to try to limit the spread.

Mutations in the Omicron variant strongly suggest that it is more contagious than previous forms of the virus, scientists say. They caution that they cannot be sure without more testing and data, but the evidence so far is sobering.

On Tuesday, the Biden administration was looking at ways to toughen coronavirus screening for people flying to the United States, including whether to require all passengers to provide a negative result from a test taken within 24 hours of departure.

周二，拜登政府正在研究对飞抵美国的旅客进行更严格的新冠病毒筛查，比如是否应要求所有乘客提供起飞前24小时内的阴性检测结果。

The concern is that the current rules, which allow fully vaccinated people to take a test up to three days before departing on a flight to the United States, might not be stringent enough.

目前的规定是让完全接种疫苗的人在乘坐航班出发前往美国前三天内进行检测，人们担心这可能还不够严格。

A day after warning that the risk from Omicron was “very high,” the World Health Organization on Tuesday said that unvaccinated people who are over age 60, are sick or have underlying health risks “should be advised to postpone travel.” In Greece, the prime minister announced that Covid vaccinations would be obligatory for people age 60 and older, and that those who failed to book a first shot by Jan. 16 would face fines.

在警告奥密克戎的风险“非常高”一天后，世界卫生组织周二表示，60岁以上、患有疾病或潜在健康风险的未接种疫苗者“应被建议推迟出行”。希腊总理宣布，60岁及以上群体必须接种新冠疫苗，到明年1月16日仍未预约第一针的人将面临罚款。

In South Africa, where the variant was first announced and is already widespread, reported new coronavirus cases have rocketed from about 300 a day in mid-November to about 3,000 a day, the fastest rate of increase in the world. On two flights from South Africa to the Netherlands on Friday, just as a cascade of bans on travel from southern Africa were being announced, 61 passengers tested positive for the virus, at least 14 of them for Omicron.

南非最早宣布该变异株的广泛传播，该国报告的新冠病例从11月中旬的每天约300例飙升至每天约3000例，增速为全球最快。上周五，就在各国针对南非的一系列旅行禁令宣布之际，从南非飞往荷兰的两架航班上，共有61名乘客检测出阳性，其中至少14人感染了奥密克戎变异株。

In addition to the question of Omicron’s transmissibility, scientists still don’t have other answers the world is clamoring for: Are vaccines less effective against it? Are treatments? Does Omicron cause more serious illness?

除了奥密克戎的传染性问题，对全世界都在密切关注的其他问题，科学家尚未给出答案：疫苗对它是否没那么有效？有治疗办法吗？奥密克戎会导致更严重的疾病吗？

Experts cautioned not to put too much stock in reports that the variant is causing only mild illness, because the data is still sparse. Early evidence from South Africa indicates that Omicron, more than previous variants, is infecting people who had already had Covid-19, but that, too, requires rigorous testing.

专家警告称，不要太相信这一变异株只会导致轻微疾病的报告，因为相关数据仍然很少。南非的早期证据表明，与此前的变异株相比，奥密克戎能感染已经得过新冠的人，但这也需要严格的检测才能查出。

“It’s going to be two to four weeks, possibly a bit sooner,” before preliminary answers are available, Dr. Anthony S. Fauci, the top U.S. infectious disease expert, said Tuesday at a White House briefing.

要得到初步答案，“得等上两到四周时间，也许能提前一点，”美国顶级传染病专家福奇在周二的白宫简报会上说道。

As of Tuesday evening, no Omicron cases had been reported in the United States, though the variant has been detected in Canada. U.S. officials say that it is just a matter of time, and that the goal should be to slow its spread.

截至周二晚间，美国还没有报告奥密克戎病例。不过，加拿大已经发现这一变异株。美国官员表示，国内发现只是时间问题，目标应该是延缓这种变异株的传播。

Brazilian media reported Tuesday that the variant had turned up in Brazil, which would mean it is already on every continent but Antarctica.

巴西媒体周二报道称，巴西出现该变异株，这意味着它已经存在于除南极洲之外的所有大洲。

The U.S. Centers for Disease Control and Prevention is sequencing the genomes of 80,000 coronavirus samples weekly — about one-seventh of all the positive P.C.R. lab tests in the country — and will step up checks on arriving international passengers, the agency’s director, Dr. Rochelle P. Wollensky, said at the White House.

美国疾病控制与预防中心主任罗谢尔·P·瓦伦斯基在白宫表示，该机构每周对80000个新冠病毒样本——占全美所有实验室核酸检测阳性样本的七分之一——进行基因组测序，并将加强对国际到达旅客的检测。

The variant has a very large number of mutations not seen in combination before, about 50, including more than 30 on the “spike” protein it uses to latch onto host cells; the spike is the primary target of the vaccines. That high degree of mutation is behind the fears about Omicron, and the uncertainty over whether those fears are overblown.

这种变异株包含了大量此前从未见过的结合突变，共有约50个，其中30多个位于它用来附着在宿主细胞之上的“刺突”蛋白质；疫苗的主要针对目标就是这类刺突蛋白质。这样的高度变异是人们恐惧奥密克戎，并无法确定这些恐惧是否被夸大的原因。

Several times before, nations have relaxed their guard, thinking that the worst of the pandemic was behind them, only to be swamped by another wave — most recently the one caused by the highly contagious Delta variant.

各国此前有几次放松了警惕，以为最严重的疫情已经过去，结果却被另一波疫情淹没——最近的一波是由传染性极强的德尔塔变异株引发的。

Vaccine makers are already looking into reformulating their shots to address Omicron, a step that was not required for fighting Delta.

疫苗生产商已经在考虑重新研发疫苗，以解决奥密克戎的威胁，对德尔塔变异株的防范尚未让他们走到这一步。

And Regeneron, maker of an effective, injected monoclonal antibody treatment for Covid, said Tuesday that its therapy might not work as well against Omicron. A U.S. Food and Drug Administration advisory panel on Tuesday recommended approval of an oral treatment to reduce the severity of Covid, made by Merck, and will soon consider another from Pfizer.

In previous waves of the pandemic, by the time the first cases of the virus or a particular variant were detected, in reality there were vastly more and it was already widespread.

在此前几波疫情中，当首次发现病毒或某一变异株的病例，实际感染数往往要多得多，而广泛传播也已经存在。

But the world’s supply of vaccines has gone primarily to the wealthiest countries, where many people have now received three shots before the vast majority of Africans have had even one. As long as many people are unvaccinated, the pandemic will continue and new variants will emerge.

但全球疫苗供应主要流向了最富裕的国家，在绝大多数非洲人一针疫苗都没打之前，富裕国家的许多人已经打完三针疫苗。只要还有如此多人未接种疫苗，疫情就会继续，新的变种也会出现。

“Vaccine equity is not charity; it’s in every country’s best interests,” Dr. Tedros Adhanom Ghebreyesus, head of the W.H.O., said Monday at the start of a conference intended to produce an international treaty to coordinate disease response.

周一，在旨在制定一项协调疾病应对的国际公约的会议开幕时，世卫组织总干事谭德塞表示，“疫苗公平不是慈善；这符合所有国家的最大利益。”

“The time has come for countries to agree on a common, binding approach to a common threat that we cannot fully control nor prevent,” he said.

“面对我们无法彻底控制或预防的威胁，各国应就具有共同约束力的办法达成一致，”他说。

Vaccine doses are in fact becoming more plentiful, but African countries still face challenges in distribution and overcoming vaccine hesitancy. South Africa recently turned away a shipment, unsure that it could use the doses in time.

The new variant was first found in Botswana on Nov. 11 and days later in neighboring South Africa, where its genome was sequenced by scientists who announced its existence two weeks later. Researchers in South Africa have found it in samples from as long ago as Nov. 9, and experts have said it was likely that further testing of old samples would show that it was circulating even earlier.

奥密克戎变种于11月11日在博茨瓦纳首次被发现，几天后出现在邻国南非，科学家在那里对其进行了基因组测序，并于两周后公布了它的存在。南非研究人员早在11月9日的样本中就发现了这一变异株，专家表示，对以往样本的进一步检测可能会发现它传播的时间更加提前。

In Europe, the number of cases confirmed is small so far, under 100, but officials are bracing for more.

在欧洲，迄今为止确诊的奥密克戎病例数量很少，不到100例，但官员们正在为感染增加做好准备。

“Is there likely to be community transmission?” Sajid Javid, the British health secretary, said at a news conference. “I think we have to be realistic: There is likely to be, as we are seeing in other European countries. We would expect cases to rise as we now actively look for cases.”

“有没有可能出现社区传播？”英国卫生部长萨吉德·贾维德在新闻发布会上表示。“我认为我们的眼光必须现实起来：正如我们在其他欧洲国家看到的那样，这种情况很可能出现。我们现在正在积极寻找病例，感染数量预计会上升。”

The timing is dismal for a continent already gripped by the biggest pandemic wave yet, forcing governments to drastically scale back plans to remain open for the holidays.

对于这个正在被迄今为止最严重的一波疫情所笼罩的大陆来说，这样的时机着实令人沮丧，各国政府将不得不全面撤销节假日期间保持开放的计划。

European countries are reporting more than two million new coronavirus cases each week, more than half the world’s total, although with vaccinations and improved treatments, deaths have declined compared with a year ago. Germany, the Netherlands, Belgium, Hungary, the Czech Republic, Slovakia, Denmark and Norway all set records for new cases last week; several others hit new highs earlier in November.

欧洲各国每周报告的新冠确诊数超过200万例，占全球确诊数的一半以上，但随着疫苗接种和治疗手段的改善，死亡人数相比一年前有所下降。上周，德国、荷兰、比利时、匈牙利、捷克共和国、斯洛伐克、丹麦和挪威的新确诊数都创下新高；另一些国家在11月初也看到了新的确诊高峰。

Governments in the United States, Europe and elsewhere have barred entry by people — usually with the exception of their own residents — who have recently been in South Africa and several neighboring countries.

美国、欧洲及其他地方的政府已经禁止最近去过南非及其几个邻国的人入境，但本国居民通常不受影响。

But the experience of the two flights that arrived in Amsterdam on Friday night from South Africa shows how late such measures might be.

而上周五晚从南非抵达阿姆斯特丹的两架航班经历的一切表明，这些措施可能为时已晚。

With the travel ban taking effect, all the passengers were tested, and more than one in 10 had the virus; how many other infected travelers have gone undetected is anyone’s guess.

由于旅行禁令生效，所有旅客都接受了检测，超过十分之一的人感染了病毒；谁都不知道有多少被感染的旅客没有被检测出来。

Not only did 14 of the passengers from South Africa have the Omicron variant — which was not yet known to the world when they took off — but they also had several different versions of it, the Dutch public health institute said.

荷兰国家公共卫生和环境研究所表示，来自南非的14名乘客不仅携带了奥密克戎变异株——在他们起飞时全世界对此还一无所知——而且还感染了该病毒的多种不同版本。

“This means,” it said, “that the people were very probably infected independently from each other, from different sources and in different locations.”

该研究所表示，“这意味着这些人的感染很可能是互不相干、来自不同感染源和不同地点的。”