英语听力—环球英语 1284 Vaccine for HIV（打印版）

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

　　And every day around the world, almost 7,000 people become newly infected with HIV, the virus that causes AIDS.

　　People call this the AIDS pandemic. So, what can we do to fight this terrible and fast-acting disease? Anthony S. Fauci is the director of the National Institute of Allergy and Infectious Diseases, in the United States. In 2012 he praised the many good ways people are trying to prevent HIV and AIDS. BUT, he said:

　　“It is likely that controlling and finally ending the HIV/AIDS pandemic will require a vaccine as well. During this past year, there have been a number of encouraging findings on this front.”

　　Viruses, like the Human Immunodeficiency Virus – spread quickly. Usually the body’s immune system can control diseases like this. But the HIV virus damages a person’s immune system. When a person gets HIV his immune system becomes weaker and weaker. His immune system cannot protect him from other diseases. Finally, HIV destroys a person’s immune system so that it no longer works. This is when a person has AIDS - Acquired Immuno Deficency Syndrome. And there is no cure for AIDS.

　　The best way to stop people from getting AIDS is to stop the HIV virus. It is very important that people know how to prevent getting HIV - and how to avoid spreading it to other people. To reduce the spread of HIV, people can follow the A B C method. People should Avoid sex before marriage. They should Be faithful to one person in marriage. And if they cannot avoid sex outside of marriage, they should always use a Condom, a rubber protective device.

　　People are also using other ways to prevent HIV. Some men are choosing to be circumcised. Mothers are reducing the chances of passing HIV to their babies. Many people with HIV are staying healthy with medicines called anti retroviral therapy [ART]. And soon, people may be able to do something else too. What if there was a way to help a person’s immune system? What if the immune system could recognize and destroy HIV before it became a problem? Some people believe a vaccine could help.

　　For over 20 years doctors have worked to create a vaccine to prevent HIV. But HIV is a very complex virus. When it copies itself it also changes in small ways. And there are different versions of the virus. For example, the most common version of HIV in South America is different than the most common version of HIV in Africa. So, it has been difficult to create a vaccine that protects against ALL versions of HIV.

　　Today doctors believe they may be close to finding a vaccine that will protect against HIV. Harriet Robinson is chief officer at GeoVax Labs. This company tests vaccines for HIV. Dr. Robinson and many other experts work with the HIV Vaccines Trials Network [HVTN]. They have tested four different HIV vaccines. Dr. Robinson told Atlanta magazine:

　　“A vaccine is possible. We are still years away. But I think we are going to have one before people think we are.”

　　Scientists must test vaccines with great care. They usually test each vaccine three or more times. Many vaccines fail on the first or second test. But some make it to the third test. At this level, doctors do a study with volunteers who choose to join the study. This kind of study is very exciting because it can show real results for people!

　　In 2009, Dr. Larry Corey of the HIV Vaccines Trails Network [HVTN] started a test with volunteers. He led an HIV vaccine study in Thailand. It was the largest AIDS vaccine trial in history! Over 16,000 Thai men and women volunteered. The volunteers were normal people ages 18 to 30. They will take the test vaccines for a total of six years.

　　This study is a double-blind study. That is, each volunteer received an injection. The injection could be the testing vaccine. Or, it could be a false vaccine. This false vaccine, or placebo, does not hurt the volunteers. But, it helps the experts to perform trustworthy tests. Only a few people keeping records know which injection each volunteer receives.

　　Vaccine studies are completely safe. Usually, a vaccine carries a whole, but weakened, version of the virus in it. But only a few genes from HIV are included in this vaccine. It is not possible for volunteers to get HIV by helping in the study. Experts do not want people to become infected with HIV. But people who are sexually active are more likely to become infected with the virus. So, during the study, experts advised volunteers about how to practice safe sex and avoid HIV. They also provided condoms for volunteers.

　　The HIV vaccine study in Thailand tested the volunteers often. By 2012 the study had results. The experts found that this vaccine reduced the infection of HIV by 30%. This means that of every three people, one less person was infected with HIV. These results are not perfect but they are important. Dr. Corey explained in a press release:

　　“These results are not at the level we will need to control the AIDS pandemic. But it is a sign that scientists WILL reach the goal of developing an HIV vaccine. There are several other vaccines that we are working on. Today's encouraging results will provide new excitement for human trials, as well as more HIV vaccine discoveries.”

　　The National Institute of Allergy and Infectious Diseases supported the Thai HIV vaccine study. Director Fauci told the New York Times:

　　“For more than 20 years now, vaccine trials have been failures. It is like we were struggling down a path with no light. And now a door has been opened. We can start asking some very important questions.”

　　So the search to find an HIV vaccine will continue. Many in the global community will not stop trying. They will not stop working until they stop the spread of HIV.

　　The writers of this program were Liz Waid and Rena Dam. The producer was Rena Dam. The voices you heard were from the United States. All quotes were adapted for this program and voiced by Spotlight. You can listen to this program again, and read it, on the internet at www.radioenglish.net. This program is called, ‘Vaccine for HIV’.

英语听力—环球英语 1284 Vaccine for HIV（在线收听）