VOA标准英语2011--US Scientists Expand Scope of HIV Vaccin

US Scientists Expand Scope of HIV Vaccine¹ Study

The world’s largest ongoing² HIV vaccine study has been expanded to consider multiple ways a vaccine might boost immune response to the AIDS virus. The U.S. Institute of Allergy³ and Infectious Diseases (NIAID) is testing the safety and efficacy of a dual⁴ vaccine candidate.
It’s called the HVTN 505 study and has been underway since June 2009. HVTN stands for the HIV Vaccine Trials Network, which is funded by the National Institutes of Health.
“The trial is being expanded both in terms of the number of participants, as well as what the trial is looking to answer,” said Mitchell Warren, head of AVAC, the AIDS Vaccine Advocacy Coalition⁵, who’s following the study’s developments.
Broader study
Enrollment⁶ is increasing from about 1300 to 2200 participants.
Originally, the study focused on whether the vaccine regimen could lower the amount of HIV in the blood if people were to become infected after being vaccinated⁷. It did not focus on whether it could actually prevent infection. Now it does.
The change stems in part from encouraging results in 2009 of the RV-144 vaccine trial in Thailand. The trial proved protection is possible, although the effectiveness was too low to go to market.
Warren said, “Because of the Thai trial, what we saw in that vaccine actually preventing infection was, wow, we really need to then look differently at HVTN 505 and expand its ability to look at the question: could this vaccine actually also prevent infection, prevent acquisition of HIV?”
Learning more, doing better
In AIDS vaccine research in the 1980s and 90s, there really was little, if any, success in getting vaccine candidates to give a protective effect. So, the emphasis switched to whether vaccines⁸ could mitigate⁹ the infection.
Warren says there are two basic immune system responses to infection.
“We have the antibody response, or the humoral immunity¹⁰, which conceptually is the part of the body that could help prevent infection. And then we have what’s called cell mediated¹¹ immunity, which is the part of the immune system that will help modulate¹² the disease if one were to be infected,” he said.
The HVTN 505 study will now try to activate¹³ both of those systems.
“It uses a prime boost combination of two different vaccines. One is a DNA¹⁴ vaccine that has snippets of HIV that can’t cause HIV at all, but is meant to kind of prime the immune system. And then it has an Adeno 5 vaccine boost,” said Warren.
Adeno 5 is actually a common cold virus. It’s used as a vector or means of delivering the vaccine.
Choose carefully
All the participants in the study fall under the UNAIDS category of Men who have Sex with Men, or MSM. The latest U.S. data show the group has a very high HIV infection rate, particularly young men of color.
It’s important for medical studies to carefully choose a target group.
“Every trial is unique and to the degree that a trial can ask a very specific question in a very specific population, the better we can answer the question. If we just created a vaccine trial or a treatment trial and said anybody can be in our trial, we just want bodies, at the end of the day we would look at the answer and say we don’t know what this means because these people were so different,” said Warren.
The HVTN 505 study is being conducted in 12 U.S. cities. The executive director of the AIDS Vaccine Advocacy Coalition calls this the most exciting time in HIV vaccine research.
The study is being led by Scott M. Hammer, M.D., the chief of NIAID’s Division of Infectious Diseases and the Harold C. Neu professor of medicine in the College of Physicians and Surgeons at Columbia University.

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 ongoing   

adj.进行中的，前进的

参考例句：

• The problem is ongoing.这个问题尚未解决。
• The issues raised in the report relate directly to Age Concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。

3 allergy   

n.(因食物、药物等而引起的)过敏症

参考例句：

• He developed an allergy to pollen.他对花粉过敏。
• The patient had an allergy to penicillin.该患者对青霉素过敏。

4 dual   

adj.双的；二重的，二元的

参考例句：

• The people's Republic of China does not recognize dual nationality for any Chinese national.中华人民共和国不承认中国公民具有双重国籍。
• He has dual role as composer and conductor.他兼作曲家及指挥的双重身分。

5 coalition   

n.结合体，同盟，结合，联合

参考例句：

• The several parties formed a coalition.这几个政党组成了政治联盟。
• Coalition forces take great care to avoid civilian casualties.联盟军队竭尽全力避免造成平民伤亡。

6 enrollment   

n.注册或登记的人数；登记

参考例句：

• You will be given a reading list at enrollment.注册时你会收到一份阅读书目。
• I just got the enrollment notice from Fudan University.我刚刚接到复旦大学的入学通知书。

7 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？

8 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。

9 mitigate   

vt.（使）减轻，（使）缓和

参考例句：

• The government is trying to mitigate the effects of inflation.政府正试图缓和通货膨胀的影响。
• Governments should endeavour to mitigate distress.政府应努力缓解贫困问题。

10 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

11 mediated   

调停，调解，斡旋( mediate的过去式和过去分词 )； 居间促成； 影响…的发生； 使…可能发生

参考例句：

• He mediated in the quarrel between the two boys. 他调解两个孩子之间的争吵。
• The government mediated between the workers and the employers. 政府在工人与雇主间搞调和。

12 modulate   

v.调整，调节(音的强弱)；变调

参考例句：

• Please modulate the sound on the TV.请调节一下电视的音量。
• This system could modulate the voice signal effectively.这个系统可以对语音信号进行有效的调制。

13 activate   

vt.使活动起来，使开始起作用

参考例句：

• We must activate the youth to study.我们要激励青年去学习。
• These push buttons can activate the elevator.这些按钮能启动电梯。

14 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。