Vaccine Makers Race to Make Changes to COVID-19 Shots

 

Vaccine¹ makers² are racing³ to make changes to their COVID-19 shots. They hope to make sure their vaccines⁴ are effective against the newest coronavirus threat even before it is clear a change is needed.

Experts doubt that current COVID-19 vaccines will become useless. But they say it is critical to see how fast companies can produce a new vaccine and prove it works. The newest version of the virus, omicron, appeared just a few weeks ago. But, scientists know it will not be the last.

Omicron "is pulling the fire alarm," said E. John Wherry. He is an immunologist at the University of Pennsylvania.

Wherry added, "Whether it turns out to be a false alarm, it would be really good to know if we can actually do this -- get a new vaccine rolled out and be ready."

It is too soon to know how vaccines will perform against omicron. Early data have been mixed: Lab tests suggest two Pfizer doses may not prevent an omicron infection but they could protect against severe illness. And a third booster shot may provide enough protection to do both.

The World Health Organization has appointed an independent scientific group to advise about possible vaccine changes. But officials have not directly said what conditions might necessitate⁵ making such changes.

Ugur Sahin is chief of BioNTech, Pfizer's vaccine partner. He said shortly before omicron's discovery that a company could propose to market a newer vaccine, "but what happens if another company makes another proposal with another variant⁶? We don't have an agreed strategy."

If vaccines are to change, there is still another question: Should there be a separate omicron booster or a combination shot? And should a combination shot target the first version of the virus along with omicron, or the currently dominant⁷ delta⁸ variant plus omicron?

Companies are not starting from the beginning

COVID-19 vaccines work by causing production of antibodies that recognize and attack the spike⁹ protein that surrounds the new coronavirus. Many of the vaccines are made with new technology that is relatively¹⁰ easy to update, or change. The Pfizer and Moderna vaccines can be changed the fastest. Those vaccines include genetic¹¹ material that directs the body to make harmless copies of the spike protein. That "messenger RNA" can be changed based on new versions of the virus.

Pfizer expects to have an omicron-specific vaccine candidate ready for the Food and Drug Administration to consider in March.

Moderna is predicting 60 to 90 days to have an omicron-specific candidate ready for testing. Other manufacturers that make COVID-19 vaccines, including Johnson & Johnson, also are working on possible updates.

Pfizer and Moderna already have successfully created experimental doses to match delta and another variant named beta. Those shots have not been needed. But the experiments offered valuable information.

Unclear if changes are needed

So far, the original vaccines have offered major protection against earlier variants¹². Pfizer's early lab testing, released Wednesday, suggests that might be the case with omicron, too.

Antibodies are not the only line of defense¹³. Vaccines also cause the growth of T cells that can prevent serious sickness from infection. Pfizer's first tests showed, as expected, T cells do not seem to be affected¹⁴ by omicron.

Also, memory cells that can create new and somewhat different antibodies form with each dose.

How to tell if updates work

The U.S. FDA has said companies would not need massive studies of updated vaccines. Instead, they would only need small studies to measure if people given the updated shot have immune reactions comparable to the original, highly effective shots.

Wherry does not expect data from volunteers testing experimental omicron-targeted shots until at least February.

What about combination shots?

Flu vaccines protect against three or four different kinds of influenza¹⁵ in one shot. If a vaccine update is needed for omicron, officials will have to decide whether to make a separate omicron booster, add it to the original vaccine, or follow the flu model and try a combination.

There is some evidence that a COVID-19 combination shot could work. In a small Moderna study, a so-called bivalent booster containing the original vaccine and a beta-specific dose caused a bigger antibody jump than either an original Moderna booster or its experimental beta-specific shot.

And scientists already are working on next-generation vaccines that target parts of the virus less likely to change.

Words in This Story

doubt - v. to be uncertain about (something) : to believe that (something) may not be true or is unlikely

alarm - n. a warning of danger

immunologist - n. a doctor who treats health issues brought on by the immune system problems (immune system: the system that protects your body from diseases and infections)

booster (shot)- n. an extra amount of a substance (called a vaccine) that is injected with a needle into a person or animal to help protect against a particular disease

original - adj. happening or existing first or at the beginning

1 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。

2 makers   

n.制造者，制造商（maker的复数形式）

参考例句：

• The makers of the product assured us that there had been no sacrifice of quality. 这一产品的制造商向我们保证说他们没有牺牲质量。
• The makers are about to launch out a new product. 制造商们马上要生产一种新产品。 来自《简明英汉词典》

3 racing   

n.竞赛，赛马；adj.竞赛用的，赛马用的

参考例句：

• I was watching the racing on television last night.昨晚我在电视上看赛马。
• The two racing drivers fenced for a chance to gain the lead.两个赛车手伺机竞相领先。

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 necessitate   

v.使成为必要，需要

参考例句：

• Your proposal would necessitate changing our plans.你的提议可能使我们的计划必须变更。
• The conversion will necessitate the complete rebuilding of the interior.转变就必需完善内部重建。

6 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。

7 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。

8 delta   

n.（流的）角洲

参考例句：

• He has been to the delta of the Nile.他曾去过尼罗河三角洲。
• The Nile divides at its mouth and forms a delta.尼罗河在河口分岔，形成了一个三角洲。

9 spike   

n.长钉，钉鞋；v.以大钉钉牢，使...失效

参考例句：

• The spike pierced the receipts and held them in order.那个钉子穿过那些收据并使之按顺序排列。
• They'll do anything to spike the guns of the opposition.他们会使出各种手段来挫败对手。

10 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

11 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。

12 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

13 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

14 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

15 influenza   

n.流行性感冒，流感

参考例句：

• They took steps to prevent the spread of influenza.他们采取措施
• Influenza is an infectious disease.流感是一种传染病。