美国国家公共电台 NPR--What's behind the FDA's controversial strategy for evaluating new COVID boosters

What's behind the FDA's controversial strategy for evaluating new COVID boosters

Transcript¹

The U.S. Food and Drug Administration is using a controversial strategy to evaluate the next generation of COVID-19 boosters.

The approach is stirring debate as the agency works to make new, hopefully improved, boosters available in September to help prevent severe disease and save lives in the fall and winter.

For the first time, the FDA is planning to base its decision about whether to authorize² new boosters on studies involving mice instead of humans.

"For the FDA to rely on mouse data is just bizarre, in my opinion," says John Moore, an immunologist at Weill Cornell Medicine in New York. "Mouse data are not going to be predictive in any way of what you would see in humans."

But others defend the approach, arguing that the country has had enough experience with the vaccines⁴ at this point to be confident the shots are safe and that there's not enough time to wait for data from human studies.

"We have 500 people a day dying of coronavirus right now. Those numbers sadly might very well rise in the fall and the winter. The question is: 'Can we do something better?'" says Dr. Ofer Levy⁵, a pediatrics and infectious disease researcher at Harvard Medical School who also advises the FDA. "And I think the answer is: 'We can, by implementing⁶ this approach.'"

The U.K. just approved a new booster

The United Kingdom just approved a new booster that targets both the original strain of the virus and the original omicron variant⁷, called BA.1 — a so-called bivalent vaccine³.

But the FDA rejected BA.1 bivalent boosters last spring. Instead, the FDA told the vaccine companies that make the mRNA vaccines, Moderna and Pfizer and BioNTech, to develop bivalent vaccines that target the dominant⁸ omicron subvariants — BA.4 and BA.5 — in the hopes they will offer stronger, longer-lasting protection.

That's why the FDA decided⁹ to use a new, streamlined strategy for testing the new boosters. The agency is asking the companies to initially¹⁰ submit only the results of tests on mice. Regulators will rely on those results, along with the human neutralizing¹¹ antibody data from the BA.1 bivalent booster studies, to decide whether to authorize the boosters.

The companies will continue to gather more data from human studies; those results probably won't be available until late October or early November.

But the big concern is the boosters may not work as well as the mouse data might suggest. Mouse experiments are notoriously unreliable.

And with the government telling people not to get the old boosters now and rejecting the first bivalent vaccines, the FDA really needs good evidence that the BA.4/5 boosters are in fact better, critics say.

"We need to make sure that we have solid immunogenicity data in people to show that you have a dramatically greater neutralizing antibody response against BA.4, BA.5," says Dr. Paul Offit of the University of Pennsylvania, who also advises the FDA. "I think anything short of that is not acceptable."

Some also worry that the approach may further erode¹² the long-faltering efforts to persuade people to get boosted.

"I think it would be good to have neutralizing antibody data in a small group of humans," says Dr. Monica Gandhi, an infectious disease researcher at the University of California, San Francisco. "Otherwise, extrapolation may be considered too great."

But others agree the time constraints¹³ mean the country can't wait for more evidence. The billions of people who have gotten Moderna and Pfizer-BioNTech mRNA vaccines show how safe they are, those experts say.

The new booster will be identical to the original vaccines except it will contain genetic¹⁴ coding for two versions of the protein the virus uses to infect cells — the protein from the original vaccine and proteins from the BA.4 and BA.5 omicron subvariants.

And some scientists say health officials know enough about how vaccines work to start handling the COVID-19 vaccines like the flu vaccines, which are changed every year to try to match whatever strains are likely to be circulating but aren't routinely tested again every year.

"We're going to use all of these data that we've learned through not only from this vaccine but decades of viral immunology to say: 'The way to be nimble is that we're going to do those animal studies," says Deepta Bhattacharya, an immunobiologist at the University of Arizona College of Medicine in Tucson. "We're really not going out too far on a limb here."

The companies are expected to submit their data to the FDA by the end of the month and the administration hopes to make millions of doses of the new boosters available starting in September.

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 authorize   

v.授权，委任；批准，认可

参考例句：

• He said that he needed to get his supervisor to authorize my refund.他说必须让主管人员批准我的退款。
• Only the President could authorize the use of the atomic bomb.只有总统才能授权使用原子弹。

3 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

4 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

5 levy   

n.征收税或其他款项，征收额

参考例句：

• They levy a tax on him.他们向他征税。
• A direct food levy was imposed by the local government.地方政府征收了食品税。

6 implementing   

v.实现( implement的现在分词 )；执行；贯彻；使生效

参考例句：

• -- Implementing a comprehensive drug control strategy. ――实行综合治理的禁毒战略。 来自汉英非文学 - 白皮书
• He was in no hurry about implementing his unshakable principle. 他并不急于实行他那不可动摇的原则。 来自辞典例句

7 variant   

adj.不同的，变异的；n.变体，异体

参考例句：

• We give professional suggestions according to variant tanning stages for each customer.我们针对每位顾客不同的日晒阶段，提供强度适合的晒黑建议。
• In a variant of this approach,the tests are data- driven.这个方法的一个变种，是数据驱动的测试。

8 dominant   

adj.支配的，统治的；占优势的；显性的；n.主因，要素，主要的人(或物)；显性基因

参考例句：

• The British were formerly dominant in India.英国人从前统治印度。
• She was a dominant figure in the French film industry.她在法国电影界是个举足轻重的人物。

9 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

10 initially   

adv.最初，开始

参考例句：

• The ban was initially opposed by the US.这一禁令首先遭到美国的反对。
• Feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。

11 neutralizing   

v.使失效( neutralize的现在分词 )；抵消；中和；使（一个国家）中立化

参考例句：

• This juice-about a quart a day--pours into my duodenum, neutralizing acids. 这种消化液（每天约分泌1品脱）流入我的十二指肠，把酸中和了。 来自辞典例句
• AIM: To verify the role of a synthetic peptide in neutralizing endotoxins. 目的：检验一条合成肽在中和内毒素活性方面的作用。 来自互联网

12 erode   

v.侵蚀，腐蚀，使...减少、减弱或消失

参考例句：

• Once exposed,soil is quickly eroded by wind and rain.一旦暴露在外，土壤很快就会被风雨侵蚀。
• Competition in the financial marketplace has eroded profits.金融市场的竞争降低了利润。

13 constraints   

强制( constraint的名词复数 )； 限制； 约束

参考例句：

• Data and constraints can easily be changed to test theories. 信息库中的数据和限制条件可以轻易地改变以检验假设。 来自英汉非文学 - 科学史
• What are the constraints that each of these imply for any design? 这每种产品的要求和约束对于设计意味着什么？ 来自About Face 3交互设计精髓

14 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。