美国要求秋季疫苗必须能对付奥密克戎

The U.S. Food and Drug Administration, or FDA, says COVID-19 booster shots for autumn will have to add protection against the latest Omicron sub-variants.
美国食品和药品管理局表示，秋季要注射的新冠疫苗加强针必须加强对奥密克戎最新子变体的保护。

Two widely used COVID-19 shots made by Moderna and Pfizer-BioNTech have saved millions of lives worldwide in just their first year of use.
由莫德纳和辉瑞生产的两种广泛使用的新冠疫苗在投入使用的第一年就挽救了全球数百万人的性命。

The FDA said they would be used for anyone still getting their first shots. But with immunity waning and the super-contagious Omicron family of variants getting better at escaping antibodies protection, the boosters will need an update. Waning immunity means that the effectiveness of the vaccine decreases over time.
美国食品和药品管理局表示，它们将用于任何仍在接种第一针的人士。但是随着免疫力的减弱和具有超强传染性的奥密克戎家族变体在逃避抗体保护方面的能力越来越强，加强针将需要进行升级。免疫力减弱意味着疫苗有效性会随着时间退役而减弱。

Fast spreading variants
快速传播的变体

Antibodies are the first layer of defense that form after vaccination or an infection. They can prevent infection by recognizing the outer coating of the new coronavirus -- the spike protein -- and blocking it from entering your cells.
抗体是接种疫苗或感染后形成的第一道防线。它们可以通过识别新冠病毒外层的刺突蛋白并阻止其进入细胞来预防感染。

Separate studies published recently in Nature and the New England Journal of Medicine show the newest sub-variants of Omicron are even better at avoiding antibodies. The studies showed this happened both in the vaccinated and in people who recovered from the original Omicron variant.
最近发表在《自然》以及《新英格兰医学杂志》上的独立研究表明，奥密克戎的最新子变体在逃避抗体方面甚至表现得更好。研究表明，这种情况既发生在接种过疫苗的人身上，也发生在感染最初的奥密克戎变体的康复者身上。

Drug companies Moderna and Pfizer said they were already working on booster shots that add protection against Omicron. The new combination shots, called "bivalent" by scientists, showed increased levels of antibodies against the original Omicron variant. But they did not provide nearly as many antibodies against its two sub-variants, known as BA.4 and BA.5. Scientists support the "bivalent" shot because it combines the original vaccines' proven benefits with new protection against other variants.
制药公司莫德纳和辉瑞表示，他们已经在研究加强对奥密克戎的保护。科学家称之为“二价”的新联合疫苗显示出对原始奥密克戎变体的抗体水平增加。但是它们没有提供那么多抗体来对付BA.4和BA.5这两个子变体。科学家支持“二价”疫苗，因为它结合了原始疫苗已证实的益处和针对其它变体的全新保护。

The Centers for Disease Control and Prevention (CDC) said the two worrisome sub-variants now make up half of all infections in the U.S. Both Moderna and Pfizer said they will have combination shots to deal with Omicron by October.
美国疾控预防中心表示，这两种令人担忧的子变体目前占到了美国所有感染的一半。莫德纳和辉瑞都表示，他们将在10月前拿出联合疫苗来应对奥密克戎。

A Pfizer spokeswoman told the Associated Press in an email: "We're continuing to collect more data from our study on BA.4/5 and will be in touch as soon as we are ready to submit." But Moderna said changing the shots to target the sub-variants might delay its version another month.
辉瑞公司的一位女发言人在电子邮件中告诉美联社：“我们将继续从我们对BA.4/5 的研究中收集更多数据，并在做好提交准备后立即与你们联系。”但是莫德纳表示，改变疫苗以针对子变体可能会让其新版疫苗推迟一个月发布。

A third company, Novavax, is awaiting FDA authorization for its more traditional, protein-based COVID-19 vaccine. Novavax argued that a booster of its regular vaccine promises higher immunity against the Omicron variant.
第三家公司诺瓦瓦克斯正在等待美国食品和药品管理局对其更传统的、基于蛋白质的新冠疫苗的授权。诺瓦瓦克斯认为，其常规疫苗加强针有望提高对奥密克戎变体的免疫力。

Decision time for the FDA
美国食品和药品管理局的决策关头

"None of us has a crystal ball" to know the next threatening variant, said FDA vaccine chief Dr. Peter Marks last week. The expression having a crystal ball means having the ability to predict the future. Marks added that the agency will try to "bring the immune system closer" to the new variants rather than the older ones.
美国食品和药品管理局疫苗负责人彼得·马克斯博士上周表示，我们谁都没有水晶球来了解下一个具有威胁的变体。拥有水晶球的是指具有预测未来的能力。马克斯还说，该机构将尝试“让免疫系统更接近”新变体，而不是旧变体。

"We would obviously like to get it right enough [so that with one more shot] we get a full season of protection," he said.
他说：“我们显然希望把它做得足够好，这样再打一针，我们就能得到一整季的保护。”

The FDA's order does not guarantee that those combination shots would be offered in autumn. Drug makers still must provide data from human trials before the agency decides whether to authorize the modified boosters. Then, the CDC would have to decide how they are used.
美国食品和药品管理局的命令并不能确保这些联合疫苗将在秋季提供。在该机构决定是否授权改善后的加强针之前，制药商仍然必须提供人体试验数据。然后，美国食品和药品管理局将必须决定如何使用它们。

It is not clear who would be offered a new combination booster shot. They might be urged only for older adults or those at high risk from the virus.
目前尚不清楚哪些人能接种最新的联合加强针疫苗。可能只会敦促老年人或高风险人群使用。

Advisers to the World Health Organization (WHO) recently said Omicron-targeted shots would be most useful as a booster because they should increase cross-protection against several variants.
世卫组织顾问最近表示，以奥密克戎为目标的疫苗作为加强针是最有效的，因为它们可以增加对几种变体的交叉保护。

Dr. Kanta Subbarao is a virologist who heads the WHO committee. "We don't want the world to lose confidence in vaccines that are currently available," she said.
坎塔·苏巴拉奥博士是领导世卫组织为会员的病毒学家。她说：“我们希望全球不要失去对现有疫苗的信心。”

I'm Jonathan Evans.
我是乔纳森·埃文斯。