VOA慢速英语--新冠疫苗是如何在创纪录的时间内研发出来的

How COVID-19 Vaccines² Developed in Record Time

Before the start of the Lunar New Year in January, Chinese officials reported an outbreak of a lung infection from a market in the city of Wuhan. There were about 41 cases of infection and one death linked to an unknown coronavirus at the time.

Some thought it was similar to the SARS virus, short for severe acute respiratory syndrome³. That virus struck southern China in late 2002. It then spread to more than 24 countries, killing⁴ nearly 800 people.

Others compared the new virus to MERS, Middle East respiratory syndrome. That coronavirus was first reported in 2012 in Saudi Arabia before spreading to 27 countries and leading to 858 known deaths.

The SARS and MERS outbreaks were mainly contained. But there are still no vaccines for those diseases.

Vaccine¹ development

Vaccine development is a long and complex process. It took 18 years for scientists to successfully develop a vaccine against polio, a disease that paralyzed many children. The College of Physicians of Philadelphia said it took two to four years just to identify a substance in the lab that could fight a disease.

But this outbreak was different. In just two months, the new coronavirus had infected more than 118,000 people in 114 countries. More than 4,200 had died from the disease.

The World Health Organization (WHO) declared the new coronavirus a pandemic on March 11. Around the world, scientists immediately went to work to develop a vaccine based on the genetic⁶ structure of the new coronavirus published on virological.com.

The WHO says there are currently more than 50 COVID-19 vaccine candidates undergoing human trials. At least 12 of the trials are in the Phase 3 level with as many as 40,000 volunteers.

This month, the United States, Britain and the European Union approved the first two vaccines, developed by Pfizer-BioNTech and Moderna, for emergency use against the new coronavirus. The approval came less than a year since the start of the pandemic.

The U.S. Food and Drug Administration (FDA) found the two vaccines from Pfizer-BioNTech and Moderna to be safe and 95 percent effective against COVID-19. The rate is well above the requirement that a vaccine be at least 50 percent effective to be considered for emergency use.

Dr. Anthony Fauci is the U.S. government's top infectious diseases expert. He said, "Not very many people expected it would be as high as that."

mRNA technology

American drug-maker Pfizer is one of the largest companies in the world. Moderna is a small biotech company that has not brought any product to the market.

But the two drug-makers have one thing in common. They both used a technology called messenger RNA, or mRNA, to develop the vaccines in record time.

Traditional vaccines usually inject an inactive or weakened virus into the body to force the production of antibodies to fight the virus. The vaccines from Pfizer and Moderna do not contain the coronavirus itself.

The mRNA vaccines give instructions for our cells to make what is called the "spike⁷ protein," a substance found on the surface of the virus that causes COVID-19. The cell then breaks down the instructions and gets rid of them. The human body recognizes that the protein does not belong there and starts producing antibodies to fight against COVID-19. At the end of the process, the body learns how to protect against future infection.

The benefit of mRNA vaccines is that those who are vaccinated⁸ gain protection without having the risk of getting sick with COVID-19.

Research behind the technology

No mRNA vaccine has been approved to treat people until now. But research on the technology started nearly 30 years ago.

In 1990, University of Pennsylvania scientist Katalin Karikó proposed using mRNA technology in gene⁵ therapy. At the time, the technology was difficult to work with. When she injected lab mice with the genetic material, some died.

Kariko worked with colleague Drew Weissman. They made an important discovery in 2005. They replaced one of mRNA's four chemical building blocks with a slightly modified substance called pseudouridine. Weissman said, "We submitted that for a patent, and that was the birth of therapeutic⁹ RNA."

Karikó and Weissman's findings, however, did not receive much attention until 2010. That year, Harvard University scientist Derrick Rossi used modified mRNA in his stem cell research. Rossi, along with several others, licensed¹⁰ the technology to establish a new biotech drug-maker called Moderna. The name is a combination of the words modified and RNA. Karikó now works for BioNTech supervising development of its mRNA product.

On December 8, Margaret Keenan of Britain became the first person in the world to receive a tested and approved COVID-19 vaccine made by Pfizer-BioNTech.

Keenan, who was to turn 91 the following week, said, "It's the best early birthday present I could wish for because it means I can finally look forward to spending time with my family and friends in the New Year after being on my own for most of the year."

Around the world, about 74 million people have been infected with the new coronavirus. Nearly 1.7 million have died from COVID-19.

Words in This Story

paralyzed –adj. unable to feel or move parts of the body

Phase 3 –n. a level of developing a vaccine when it is tested on people to better understand their reactions

therapy –n. treatment for an illness

submitted –v. offered for review and approval

patent –n. an official document that gives a person the right to be the only seller of a product for a period of time

therapeutic –adj. related to treatment and therapy

licensed –v. having official permission to have something or receive gain from it

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 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

4 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

5 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

6 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。

7 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。

8 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？

9 therapeutic   

adj.治疗的，起治疗作用的；对身心健康有益的

参考例句：

• Therapeutic measures were selected to fit the patient.选择治疗措施以适应病人的需要。
• When I was sad,music had a therapeutic effect.我悲伤的时候，音乐有治疗效力。

10 licensed   

adj.得到许可的v.许可，颁发执照(license的过去式和过去分词)

参考例句：

• The new drug has not yet been licensed in the US. 这种新药尚未在美国获得许可。
• Is that gun licensed? 那支枪有持枪执照吗？