英语听力—环球英语 467：Making a Life-Saving Medicine

　　Voice 1

Welcome to Spotlight 1. I’m Joshua Leo.

Voice 2

And I’m Christy VanArragon. Spotlight uses a special English method of broadcasting. It is easier for people to understand no matter where in the world they live.

Voice 1

It was a fearful picture. Children, unable to walk. Children, unable to breathe. Every summer, people saw this image repeated – the polio disease had returned. What caused this terrible disease? How could it be prevented? Today’s Spotlight is on Jonas Salk and the polio vaccine 2.

Voice 2

Polio is a very serious disease. It is often spread by infected human waste. Usually, people become sick with polio after drinking or touching 3 dirty water or waste. Many children become infected by swimming in infected water. Polio affects a person’s nerves. It can make a person unable to move. In the worst cases, a person may not be able to breathe. Polio was a big concern in the United States and Europe in the 1940’s and 1950’s. Many people became sick every summer. These epidemics 4 were getting worse. And people were very afraid. Many scientists had tried to develop vaccines 5, but none were successful. Jonas Salk wanted to stop the disease quickly.

Voice 1

Jonas Salk was a doctor and scientist in the United States. In the 1940’s, he developed an important influenza 6 vaccine. Vaccine medicines prepare a person’s body to fight a particular virus, or disease. Usually scientists would make a weak version of the virus and inject it into a person’s body. The body then creates antibodies against this virus. These cells fight specific viruses. The body can fight this weak virus and prepare to fight the normal virus when the time comes.

Voice 2

But this can be dangerous. Sometimes, a person becomes sick with the virus they are trying to prevent. So Salk and his partner Thomas Francis wanted to make their vaccine differently. They used a version of the influenza vaccine that was dead. The body was still able to create antibodies against the virus, but there was no risk of infection. This was successful for influenza. And it prepared the way for Salk’s work on polio.

Voice 1

Salk then went on to study how vaccines affect people. He also spent time researching the polio virus. Salk wrote a few papers about polio. Daniel O’Connor read some of these papers. He worked for the National Foundation of Infantile Paralysis 7. This group worked to fight the polio virus. O’Connor asked to meet Salk. When they met, O’Connor liked Salk. O’Connor decided 8 to give most of the group’s money to Salk’s research for a polio vaccine.

Voice 2

Some scientists were not happy that Salk received the money for his research. Many other scientists had been studying polio longer than Salk. Some people thought that these scientists deserved the money. But Jonas Salk just kept working hard trying to find a cure.

Voice 1

First, Salk had to get enough of the polio virus to study. This was difficult. Viruses need living cells to grow. They do not live on their own. But a group of scientists had found a way to grow the virus. Salk used their method to move on with his research. Salk decided to make the polio vaccine like he made the influenza vaccine. He would use a killed virus instead of a weakened one.

Voice 2

Jonas Salk first tested his polio vaccine on a group of children in 1952. They already had polio. After the vaccine, these children had many more antibodies in their bodies. This was a good sign. The vaccine helped the children fight the virus.

Voice 1

Salk was now ready to test the vaccine on people who did not have the disease. First, he tested it on himself and his family. It was safe. It seemed to work. In 1954 he tested the vaccine with over four hundred thousand [400,000] children. The children were split up into three groups. One group received the vaccine. Another group received a placebo 9, a vaccine that does nothing. And the last group was not given anything.

Voice 2

The vaccine tests went well. Soon news groups wanted to know about this new polio vaccine. Even though the test was not complete, Salk talked to the press. People were very excited about a possible cure to the disease, and Salk was excited too. But some other scientists were not happy with Salk. They said that Salk did not follow the right process of releasing information.

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The scientists said that Salk should have waited until the test was complete to discuss the vaccine. He should have published his research in a medical journal so other scientists could see it first. The scientists claimed that Salk just wanted to become famous for discovering the cure for polio. This hurt Salk. He said he only had the best goals in mind. He wanted to help people.

Voice 2

In 1955, Jonas Salk’s polio vaccine was declared to be a success. By the end of 1955 seven million children had received vaccine injections. By the summer of 1961, the cases of polio had dropped by ninety–six [96] percent. Soon many other countries were using polio vaccines too.

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The success made Jonas Salk famous. He was given a national award for medicine. He was also nominated for a Nobel Prize. But Salk also faced challenges. Some scientists still did not like him. Jonas Salk could not join the National Academy of Sciences, an important scientific group. And many scientists did not think he deserved the recognition he received.

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But Salk’s success did let him continue work on curing diseases. In 1963, Jonas Salk opened the Salk Institute for Biological Studies. It was a place where the best scientists could work together to cure diseases and create vaccines.

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Because of Salk, and other scientists’, work, polio is gone in many countries around the world. But it still affects many people in Nigeria, India, and Pakistan. Aid groups are spreading the polio vaccine to those who still need it. Today, Salk’s vaccine is not used as much. This version of the vaccine uses the weakened virus instead of a killed one. Instead of an injection, it can be given as a pill in the mouth. It is easier for aid groups to give people, and it works better. Using the polio vaccine, doctors and aid groups hope to stop polio forever in the next few years. This goal would never have been possible without the important work of Jonas Salk.