VOA健康报道2024--Scientists Test mRNA Vaccines to Protect Against Bird Flu

Scientists Test mRNA Vaccines² to Protect Against Bird Flu

From VOA Learning English, this is the Health & Lifestyle report.

Scientists are testing next-generation vaccines to deal with the spread of bird flu in the United States. The vaccines use the same mRNA technology that led to the development of COVID-19 shots in record time.

The U.S. Agriculture Department is planning to test a vaccine¹, developed by University of Pennsylvania researchers, by giving it to cows in order to protect farm workers. They say this could lessen³ the chance for the virus to jump into people and mutate, or change, in ways that could cause human-to-human spread.

Meanwhile, officials at the U.S. Department of Health and Human Services have been talking to drugmakers about possible mRNA flu vaccines for people. These mRNA vaccines would be in addition to the millions of bird flu vaccines already in government hands.

“If there’s a pandemic, there’s going to be a huge demand for vaccine,” said Richard Webby, a flu researcher at St. Jude Children’s Research Hospital in Memphis. The more vaccines, the better, he added.

Spread of bird flu virus

Since 2020, the bird flu virus has been spreading among different kinds of animals in many countries. In March, it was found in U.S. dairy cows. However, investigators⁵ think it may have been in cows since December. Recently, the USDA announced it had been found in alpacas for the first time.

At least three dairy farm workers in the U.S. have been diagnosed with bird flu. Their illnesses were not severe. But earlier versions of the same H5N1 flu virus have been deadly to humans in other parts of the world. And U.S. officials are taking steps to be prepared if the virus mutates to a deadlier version or permits it to spread more easily from person to person.

Health officials say they already have two candidate vaccines for people that appear to be well-matched to the bird flu virus in U.S. dairy cows. They say, hundreds of thousands of prepared vaccines could go out immediately. And nearly 10 million more treatments could be produced in a few months.

The drugmaker CSL Seqirus said the U.S. government hired it to fill and finish about 4.8 million shots that could be completed by late summer. But the production lines for flu vaccines are already working on this autumn’s seasonal⁶ shots. And drugmakers would have to stop the lines to produce the bird flu vaccine.

Looking for a faster pathway

So, the government has been looking for another, faster pathway: the mRNA technology used by drugmakers Moderna and Pfizer to produce the vaccines against COVID-19.

Vaccine makers⁴ usually add elements of an inactive or weakened virus to the shot mixture. But with mRNA vaccines, scientists instead create a genetic⁷ material to direct the human body to produce antibodies and recognize and destroy the virus.

Moderna already has a bird flu mRNA vaccine in very early testing in humans. In a statement, Moderna said they “are in discussions with the U.S. government on advancing our pandemic flu candidate.”

Similar work has been going on at Pfizer. Company researchers in December gave human volunteers an mRNA vaccine against a version of bird flu that is somewhat similar to the one in cows.

Since then, researchers have performed a lab experiment exposing blood samples from those volunteers to the version seen in dairy cows. Pfizer said in a statement that they saw “notable increases in antibody responses.”

As for cows, University of Pennsylvania researcher Scott Hensley worked with Nobel-prize winner Drew Weissman on an experimental vaccine similar to the Moderna one for people.

In first-step testing, mice and ferrets produced high levels of bird flu virus-fighting antibodies after vaccination⁸.

In another experiment, researchers infected one group of ferrets after vaccination. Then they compared what happened to unvaccinated ferrets. All the vaccinated⁹ animals survived and the unvaccinated did not, Hensley said.

“The vaccine was really successful,” said Webby of St. Jude Children’s Research Hospital in Memphis. His lab did that work last year in partnership¹⁰ with Hensley.

The cow study will be similar to the early testing done in smaller animals. The plan is for about 10 small cows to be vaccinated, half with one shot and half with another. Then their blood will be examined to look for how much bird flu-fighting antibodies were produced.

Hensley said that if a vaccine reduces the amount of virus in the cow, “then ultimately we reduce the chance that a mutant virus that spreads in humans is going to emerge.”

That’s the Health & Lifestyle report.

Words in This Story

mutate – v. to cause to undergo changes at the genetic level (mutation)

dairy – n. milk from a cow or other domestic animal (such as a goat)

diagnose – v. to recognize (something, such as a disease) by signs and symptoms

advance – v. to bring or move forward

sample – n. a part (as a set of individuals chosen from a whole population) used for investigating the whole

response – n. a reaction of a living thing to a stimulus¹¹

ultimately – adv. in the end

emerge – v. to become known or apparent

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 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。

3 lessen   

vt.减少，减轻；缩小

参考例句：

• Regular exercise can help to lessen the pain.经常运动有助于减轻痛感。
• They've made great effort to lessen the noise of planes.他们尽力减小飞机的噪音。

4 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》

5 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

6 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

7 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。

8 vaccination   

n.接种疫苗，种痘

参考例句：

• Vaccination is a preventive against smallpox.种痘是预防天花的方法。
• Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。

9 vaccinated   

[医]已接种的，种痘的，接种过疫菌的

参考例句：

• I was vaccinated against tetanus. 我接种了破伤风疫苗。
• Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗？

10 partnership   

n.合作关系，伙伴关系

参考例句：

• The company has gone into partnership with Swiss Bank Corporation.这家公司已经和瑞士银行公司建立合作关系。
• Martin has taken him into general partnership in his company.马丁已让他成为公司的普通合伙人。

11 stimulus   

n.刺激，刺激物，促进因素，引起兴奋的事物

参考例句：

• Regard each failure as a stimulus to further efforts.把每次失利看成对进一步努力的激励。
• Light is a stimulus to growth in plants.光是促进植物生长的一个因素。