VOA常速英语2007年-Oral Cholera Vaccine Found Highly Effective

By Jessica Berman
Washington
27 November 2007

Endemic cholera¹, a potentially fatal diarrheal disease found in the world's poorest countries, could be effectively controlled by orally vaccinating² half of the affected³ populations once every two years for only pennies per dose, according to new findings by an international team of researchers.  The conclusion is based on a computer model of the vaccine⁴'s effectiveness.  VOA's Jessica Berman reports.

Cholera causes massive fluid loss that can kill.  While oral rehydration therapy has made the disease treatable, each year an estimated 100,000 to 500,000 people die from it.

Cholera is caused by ingesting contaminated food or water. 
 
For years, Western travelers to cholera-endemic countries have been offered an oral vaccine to protect them, but the drugs have never been used in epidemics⁵, partly because of questions about their effectiveness.  But a new study suggests the oral cholera vaccine is highly effective in controlling outbreaks. 

Ira Longini is a statistician with the Fred Hutchinson Cancer Research Center in Seattle, Washington, and the study's lead author. 

"We really believe that cholera, which is on the move throughout the planet, is very controllable with very cheap and effective vaccines⁶ [that] are there," Longini said.

Using the results from a large-scale trial involving 200,000 women and children in a rural area of Bangladesh between 1984 and 1989, researchers from the United States,  South Korea, and India created a computer model to predict the effectiveness of the cholera vaccine.

According to the model, if 50 percent of the people who live in a high-risk community receive the cholera vaccine once every two years, Longini says the number of new cholera cases would be reduced by 90 percent, to less than one case in a thousand unvaccinated people.

That is because the vaccine against cholera confers what one researcher described as "herd⁸ immunity⁹" - protection of non-vaccinated⁷ neighbors of vaccinated persons.

The study is published in the on-line journal Public Library of Science.

Longini says immunizing people with a cheap oral cholera vaccine would be easy.

"We have very good prediction[s] about where cholera transmission is likely to occur, so, you could really have it focused where cholera is and just concentrate on those populations," Longini said.

The study was supported by the South Korean International Vaccine Institute, with ties to the World Health Organization, and the Bill and Melinda Gates Foundation, which supports global health programs. 

1 cholera   

n.霍乱

参考例句：

• The cholera outbreak has been contained.霍乱的发生已被控制住了。
• Cholera spread like wildfire through the camps.霍乱在营地里迅速传播。

2 vaccinating   

给…接种疫苗( vaccinate的现在分词 )； 注射疫苗，接种疫苗

参考例句：

• At first blush, vaccinating the wolves against rabies seems a simple solution. 乍一看来，为狼群注射防狂犬病疫苗是一种简单的办法。
• Also vaccinating children against misers (measles) has saved many lives. 还有，给儿童进行疫苗接种防止麻疹也挽救了许多生命。

3 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

4 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。

5 epidemics   

n．流行病

参考例句：

• Reliance upon natural epidemics may be both time-consuming and misleading. 依靠天然的流行既浪费时间，又会引入歧途。
• The antibiotic epidemics usually start stop when the summer rainy season begins. 传染病通常会在夏天的雨季停止传播。

6 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。

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 herd   

n.兽群，牧群；vt.使集中，把…赶在一起

参考例句：

• She drove the herd of cattle through the wilderness.她赶着牛群穿过荒野。
• He had no opinions of his own but simply follow the herd.他从无主见，只是人云亦云。

9 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。