Experts Discuss How to Update COVID Vaccines

More than two years into the COVID-19 pandemic, United States health officials are discussing how to best protect Americans from the ever-changing coronavirus.

On Wednesday, a group of vaccine¹ advisers² to the Food and Drug Administration spent hours debating questions about changing vaccine shots and doing future booster campaigns. They did not reach any exact decisions.

The questions facing the experts included: How often should vaccines³ be updated against new strains? How effective should vaccines be to get government approval? Should vaccine updates be coordinated⁴ with international health authorities?

Background

The FDA recently approved a fourth shot of the Pfizer or Moderna vaccines for anyone 50 or older and for some younger people with severely⁵ weakened immune systems. The move is part of an effort to get ahead of another possible surge.

But the FDA's vaccine chief Dr. Peter Marks said at the meeting "we simply can't be boosting people as frequently as we are." He called the latest booster update a temporary measure to protect Americans while government officials decide whether and how to change current vaccines.

Marks cautioned that reduced vaccine protection, new variants⁷ and colder weather in the autumn could raise the risk of more surges.

Future booster shots?

One area where experts appeared to agree is that vaccines should be judged on their ability to prevent severe disease that leads to hospitalization and death.

Dr. Mark Sawyer of the University of California, San Diego, said, "We need to focus on the worst case, which is severe disease..."

By that measure, the current vaccines have held up well.

During the last omicron-driven surge, two vaccine doses were nearly 80 percent effective against needing a breathing machine or death — and a booster pushed that protection to 94 percent, federal scientists recently reported.

But only about half of Americans eligible⁸ for a third shot have gotten one. And many experts said it was not the best idea to continue asking Americans to get boosted every few months.

An expert from the Centers for Disease Control and Prevention suggested that the 80 percent protection from severe disease could become the standard for vaccines.

"I think we may have to accept that level of protection" and then use other methods, said Dr. Amanda Cohn, CDC's chief medical officer.

Presentations at the meeting by government health officials and independent researchers explored the difficulty of predicting when the next major COVID-19 variant⁶ might appear.

Trevor Bedford of the Fred Hutchinson Cancer Research Center said a major new strain like omicron could arrive anywhere from every 1.5 years to once a decade, based on current data.

Process for updating vaccines

All three COVID-19 vaccines now used in the U.S. are based on the original coronavirus that appeared in late 2019. Updating the vaccines will be a difficult job, likely requiring communication between the FDA, manufacturers and international health authorities.

To get the vaccines to market quickly, the FDA used shorter ways to judge effectiveness, mainly looking at the early vaccine effects on the immune system's antibody levels. A number of experts said they wanted better data from studies that follow patients over time to see who gets sick or dies.

But that approach would likely take too much time.

Dr. Ofer Levy⁹ of Harvard Medical School said, "it's going to be hard to generate all the data we want in short order when a new variant emerges."

Robert Johnson, a representative for the U.S. Biomedical Advanced Research and Development Authority (BARDA) described the small amount of time that manufacturers could have to remake, study and mass produce an updated vaccine by September.

"If you're not on your way to a clinical trial by the beginning of May, I think it's going to be very difficult to have enough product across manufacturers to meet demand," he said.

The process for updating yearly flu vaccines offers a possible plan, as laid out by a representative from the World Health Organization.

Twice a year, WHO experts recommend updates to flu vaccines to target new strains. The FDA then brings those recommendations to its own vaccine panel, which votes on whether they make sense for the U.S.

But COVID-19 has not yet fallen into a predictable pattern like the flu. And as the coronavirus evolves, different strains may become stronger in different parts of the world.

Several experts said they would need more meetings with more data and proposals from the FDA to decide on a plan.

Oveta Fuller of the University of Michigan's Medical School said, "We've never been here before. We're all working together to do the best we can and it's very complex."

Words in This Story

booster – n. a substance or dose used to renew or increase the effect of a drug or immunizing agent

surge -- n. a sudden and large increase

variant -- n. something that is slightly different from the standard form

focus – v. to concentrate attention or effort

eligible – adj. qualified¹⁰ to participate or be chosen

approach -- n. a particular manner of taking such steps

standard – n. something set up and established by authority as a rule for the measure of quantity, weight, extent, value, or quality

generate – v. to bring into existence:

pattern – n. a reliable sample of traits, acts, tendencies, or other observable characteristics

evolve -- v. to undergo evolutionary change

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 advisers   

顾问，劝告者( adviser的名词复数 )； （指导大学新生学科问题等的）指导教授

参考例句：

• a member of the President's favoured circle of advisers 总统宠爱的顾问班子中的一员
• She withdrew to confer with her advisers before announcing a decision. 她先去请教顾问然后再宣布决定。

3 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。

4 coordinated   

adj.协调的

参考例句：

• The sound has to be coordinated with the picture. 声音必须和画面协调一致。
• The numerous existing statutes are complicated and poorly coordinated. 目前繁多的法令既十分复杂又缺乏快调。 来自英汉非文学 - 环境法 - 环境法

5 severely   

adv.严格地；严厉地；非常恶劣地

参考例句：

• He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
• He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

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 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

8 eligible   

adj.有条件被选中的；(尤指婚姻等)合适(意)的

参考例句：

• He is an eligible young man.他是一个合格的年轻人。
• Helen married an eligible bachelor.海伦嫁给了一个中意的单身汉。

9 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。

10 qualified   

adj.合格的，有资格的，胜任的，有限制的

参考例句：

• He is qualified as a complete man of letters.他有资格当真正的文学家。
• We must note that we still lack qualified specialists.我们必须看到我们还缺乏有资质的专家。