好英语网新冠亚变体XBB.1.5有什么特点？我们应该担心吗？
Coronavirus cases and hospitalizations have steadily ticked up in the United States over the past couple months. This is due, at least in part, to half a dozen subvariants that seem to be better at immune evasion and at transmission than previous virus versions.
在过去几个月里，美国的新冠病例和住院人数不断上升。这至少部分是由于六个亚变体导致的，它们似乎比以前的病毒变体更擅长免疫逃避和传播。
Now, one subvariant, XBB.1.5, seems to be spreading even faster. A hybrid of two BA.2 variants and a relative of the so-called “nightmare variant,” XBB, which caused a surge in Singapore in the fall, XBB.1.5 is raising concerns about a potential wave in the United States as people return from holiday travel.
现在，其中一个亚变体XBB.1.5似乎传播得更快。它是两个BA.2变体的混合体，所谓的“噩梦变体”的XBB的亲戚，XBB在秋季引起了新加坡的病例激增。眼下正值人们从假期旅行返回，XBB.1.5引发了对美国潜在感染浪潮的担忧。
According to the Centers for Disease Control and Prevention, XBB.1.5 nearly doubled in prevalence every week in December. Just before Christmas, it accounted for 21.7 percent of new Covid cases in the United States. In an update on Dec. 30, the C.D.C. said that XBB.1.5 made up 40.5 percent of cases and had edged out the other subvariants (like BA.5, BF.7, BQ.1 and BQ.1.1, among others) that are currently responsible for the rest of the cases in the U.S. In the Northeast, XBB.1.5’s foothold is even stronger: It is causing roughly 75 percent of new cases.
根据疾病控制和预防中心的数据，XBB.1.5的流行率在12月的每周几乎都翻了一番。就在圣诞节前夕，它占美国新增新冠病例的21.7%。疾控中心在12月30日的更新中表示，XBB.1.5占病例的40.5%，并且已经挤掉了目前导致美国其余病例的其他子变体（如BA.5、BF.7、BQ.1和BQ.1.1等）。在东北部，XBB.1.5的优势更是明显：造成了大约75%的新病例。
Here’s what experts know so far about the new subvariant and what its mutations may mean for repeat infections, symptoms, case numbers and treatment options.
以下是迄今为止专家们对新亚变体的了解，以及它的突变对重复感染、症状、病例数和治疗方案可能意味着什么。
How worried should I be?
问题有多大？
The evolution of coronavirus variants is nothing new. “Viruses and pathogens are constantly trying to adapt and escape the immune pressure that we pose to them,” said Dr. Albert Ko, a physician and epidemiologist at the Yale School of Public Health.
新冠病毒变体的演化并不是什么新鲜事。“病毒和病原体一直在努力适应和逃避我们对它们施加的免疫压力，”耶鲁大学公共卫生学院的医师兼流行病学家阿尔伯特·柯说。
XBB.1.5 is slightly different from its relatives, because it not only evades protective antibodies, it also is better at binding to cells. That means healthy adults are more likely to be infected with it even after vaccination or an infection with a different variant.
XBB.1.5与其亲属略有不同，因为它不仅可以逃避保护性抗体，还可以更好地与细胞结合。这意味着健康的成年人即使在接种疫苗或感染不同毒株后也更容易感染该变异株。
But other parts of the immune system can still come to our defense, said Dr. Otto Yang, an infectious disease physician and immunology researcher at David Geffen School of Medicine at the University of California, Los Angeles.
但免疫系统的其他部分仍然可以为我们提供防御，加州大学洛杉矶分校大卫·格芬医学院的传染病医师和免疫学研究员奥托·杨说。
Even if mutations in some parts of the virus prevent antibodies from blocking an infection, T cells should be able to recognize the main part of the virus spike protein, Dr. Yang said. And because T cells remember how to respond to the coronavirus based on what they’ve learned from previous encounters or vaccines, they can mount an attack quickly if you do become infected. “They are what prevent severe illness,” Dr. Yang said. “People who are up to date on their vaccines and who get treatment early with Paxlovid or with remdesivir are going to do fine, for the most part.” (Paxlovid is an oral antiviral medication, and remdesivir is an injectable one.)
杨说，即使病毒某些部分的突变使抗体无法阻断感染，T细胞也应该能够识别病毒刺突蛋白的主要部分。而且由于T细胞会根据它们从过去的感染或疫苗中学到的经验知道如何对新冠病毒做出反应，因此如果你真的被感染了，它们可以迅速发起攻击。“它们可以预防重病，”杨说。“在大多数情况下，那些及时接种疫苗并及早接受奈玛特韦/利托那韦(Paxlovid)或瑞德西韦(remdesivir)治疗的人都会没事。”（奈玛特韦/利托那韦是一种口服抗病毒药物，瑞德西韦是一种注射药物。）
Immune evasion and infection are a bigger concern for people who are immunocompromised or who do not mount a strong immune response to vaccines. That includes people who have had stem cell or solid organ transplants, people receiving cancer treatments, people with autoimmune diseases and people who need immunosuppressive medication for various medical conditions, said Dr. Alpana Waghmare, an infectious disease expert at Fred Hutchinson Cancer Center.
免疫逃避和感染对于免疫功能低下或对疫苗没有强烈免疫反应的人来说是一个更大的问题。弗雷德·哈钦森癌症中心的传染病专家阿尔帕纳·瓦赫玛说，这包括接受过干细胞或实体器官移植的人、接受癌症治疗的人、患有自身免疫性疾病的人以及需要针对各种医疗状况使用免疫抑制药物的人。
The antibody treatments that many immunocompromised people have relied on, like the preventive shot Evusheld and the intravenous Covid treatment bebtelovimab, are not effective against XBB.1.5 and other new subvariants. As a result, immunocompromised people may have more severe disease, but other antiviral treatments will most likely keep deaths from increasing in this group.
许多免疫功能低下的人所依赖的抗体治疗，如预防性注射恩适得(Evusheld)和静脉注射新冠治疗贝替洛维单抗(bebtelovimab)，对XBB.1.5和其他新亚变异株无效。因此，免疫功能低下的人可能会患上更严重的疾病，但其他抗病毒治疗很可能会阻止这一群体的死亡人数增加。
What are the symptoms of a Covid-19 infection with the new subvariants?
感染新冠病毒新亚变体的症状是什么？
There is no evidence yet to suggest that people who are infected with any of the new subvariants experience new or unusual symptoms or that their illness is more severe than what we’ve seen with previous Omicron variants, Dr. Waghmare said.
瓦赫玛说，目前还没有证据表明感染任何新亚变体的人会出现新的或不寻常的症状，或者他们的疾病比我们在之前的奥密克戎变体中看到的更严重。
The most common symptoms still include a mild runny nose, headache and sore throat. These could precede a positive Covid test, and symptoms could be mild or moderate for the duration of the illness.
最常见的症状仍然包括轻微的流鼻涕、头痛和喉咙痛。这些症状可能会在新冠检测呈阳性之前出现，发病期间症状为轻度或中度。
How can I protect myself against the virus?
如何防御这种病毒？
The best thing most people can do to protect themselves is to be vaccinated and boosted. In particular, those who are at high risk, as well as those who have not had a booster shot or a Covid infection in the last four to six months, should make a plan to get a shot, Dr. Yang said. Some experts recommend a booster even sooner.
大多数人自我保护的最好方式就是接种疫苗和加强针。奥托·杨说，特别是那些高危人群以及在过去四到六个月没有打加强针或没有感染过新冠的人，更应该做好接种疫苗的准备。有专家甚至建议尽早接种加强针。
The bivalent booster can train your immune system to recognize the original virus from 2020 as well as the BA.5 Omicron variant. Although it remains to be seen how well antibodies from the bivalent shot may work against XBB.1.5, the T cell protection that arises from the booster should still be able to protect you against severe illness if you are infected, Dr. Yang said. In terms of vaccine effectiveness, “if we see that deaths are reduced and if serious illness and hospitalizations are reduced, even if people do get infected, that’s still a big success,” said Michael Osterholm, an epidemiologist and the director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
二价加强针可以让免疫系统学会识别2020年的原始毒株以及BA.5奥密克戎变异株。杨说，虽然二价疫苗产生的抗体抵御XBB.1.5的能力还有待观察，但如果被感染，靠加强针产生的T细胞防护仍能保护人体免受严重疾病的影响。就疫苗有效性而言，“如果我们看到死亡人数减少，患上严重疾病和住院的人数减少，那就算人们确实会被感染，也还是巨大的成功，”流行病学家兼明尼苏达大学传染病研究和政策中心主任迈克尔·奥斯特霍尔姆表示。
People who are at high risk of severe Covid-19 or have vulnerable family members should also consider wearing a mask, avoiding crowded indoor venues and asking others about Covid symptoms or exposure, particularly after gatherings. They should also take frequent Covid tests and seek antiviral medication such as Paxlovid early on if a test comes back positive, Dr. Osterholm said.
如果是新冠重症高危人群或是家人属于易感人群，应该考虑佩戴口罩，避免进入拥挤的室内场所，并询问其他人的新冠症状或接触病毒的情况，特别是在聚会之后。奥斯特霍尔姆表示，这些人还应该频繁进行新冠检测，如果呈阳性应尽早使用奈玛特韦/利托那韦等抗病毒药物进行治疗。