VOA标准英语2010年-Scientists Take Steps Toward Universal

Each year, scientists work to develop a unique influenza¹ vaccine² to protect people against the strain expected in the coming flu season. Mutations in the virus mean that last year's vaccine probably won't protect against this year's flu variety. Now, a team of U.S. scientists think they're on track to developing a "universal" vaccine that will protect people against all kinds of influenza.

The standard flu vaccine causes the body to produces antibodies, which target parts of the virus that frequently mutate. But in a new study, researchers used a vaccine aimed at a different part of the virus.

"There are parts of the flu virus that could be the target of what we would hope eventually could be a universal influenza vaccine," said Gary Nabel, who heads the U.S. government's Vaccine Research Center at the National Institute of Allergy³ and Infectious Diseases of the National Institutes of Health and was the study's lead author.

"They don't mutate, and the reason they don't mutate is that if they try to, the virus can't survive if you have mutations in these sites."

To get at these non-mutating parts of the virus, Nabel and his colleagues used a two-step vaccination⁴ process, called "prime-boost." The first step uses a bit of influenza DNA⁵ to get the patient's immune system to begin fighting off the flu, and then the protection is given a "boost" some time later by the second step, which can be either another bit of DNA or a conventional flu vaccine.

In his paper, which was published online by the journal Science, Nabel describes the results of animal tests in ferrets and mice using the 1999 vaccine for the boost.

"The antibodies that we were able to elicit⁶ could neutralize⁷ [varieties of flu virus] as far back as 1934 and as recently as 2007. So it really gave a broad coverage⁸ against a range of seasonal⁹ viruses that wouldn't be covered by the traditional flu vaccine," he said.

Preliminary phase one tests of this new type of flu vaccine have already started in humans, but in an interview, Nabel said that even if all goes well, it will still be years before a universal flu vaccine is widely available.

"So it's certainly not going to be with us in anything less than three years, and I think it's more likely that we're in a five to ten year time frame."

Gary Nabel of the U.S. Vaccine Research Center points out that his universal flu vaccine would have another benefit. A DNA-based vaccine wouldn't have to be grown in chicken eggs, doing away with the time-consuming and finicky manufacturing process of the current flu vaccine.
 

1 influenza   

n.流行性感冒，流感

参考例句：

• They took steps to prevent the spread of influenza.他们采取措施
• Influenza is an infectious disease.流感是一种传染病。

2 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。

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 vaccination   

n.接种疫苗，种痘

参考例句：

• Vaccination is a preventive against smallpox.种痘是预防天花的方法。
• Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。

5 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。

6 elicit   

v.引出,抽出,引起

参考例句：

• It was designed to elicit the best thinking within the government. 机构的设置是为了在政府内部集思广益。
• Don't try to elicit business secrets from me. I won't tell you anything. 你休想从我这里套问出我们的商业机密, 我什么都不会告诉你的。

7 neutralize   

v.使失效、抵消，使中和

参考例句：

• Nothing could neutralize its good effects.没有什么能抵消它所产生的好影响。
• Acids neutralize alkalis and vice versa.酸能使碱中和碱，亦能使酸中和。

8 coverage   

n.报导，保险范围，保险额，范围，覆盖

参考例句：

• There's little coverage of foreign news in the newspaper.报纸上几乎没有国外新闻报道。
• This is an insurance policy with extensive coverage.这是一项承保范围广泛的保险。

9 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。