来源:网络 2019-02-25


      Modern technology has put men on the moon and deciphered the human genome. But when it comes to brewing up flu to make vaccines, science still turns to the incredible edible egg. Ever since the 1940s, vaccine makers have grown large batches of virus inside chicken eggs. But given that some 36,000 Americans die of flu each year, its remarkable that our first line of defense is still what Secretary of Health and Human Services Tommy Thompson callsthe cumbersome and archaic egg-based production.” New cell-based technologies are in the pipeline, however, and may finally get the support they need now that the United States is faced with a critical shortage of flu vaccine. Although experts disagree on whether new ways of producing vaccine could have prevented a shortage like the one happening today, there is no doubt that the existing system has serious flaws.

Each year, vaccine manufacturers place advance orders for millions of specially grown chicken eggs. Meanwhile, public-health officials monitor circulating strains of flu, and each March they recommend three strainstwo influenza A strains and one B strainfor manufacturers to include in vaccines. In the late spring and summer, automated machines inject virus into eggs and later suck out the influenza-rich goop. Virus from the eggsinnards gets killed and processed to remove egg proteins and other contaminants before being packaged into vials for fall shipment.

Why has this egg method persisted for six decades? The main reason is that its reliable. But even though the eggs are reliable, they have serious drawbacks. One is the long lead time needed to order the eggs. That means its hard to make more vaccine in a hurry, in case of a shortage or unexpected outbreak. And eggs may simply be too cumbersome to keep up with the hundreds of millions of doses required to handle the demand for flu vaccine.

Whats more, some flu strains dont grow well in eggs. Last year, scientists were unable to include the Fujian strain in the vaccine formulation. It was a relatively new strain, and manufacturers simply couldnt find a quick way to adapt it so that it grew well in eggs. “We knew the strain was out there,” recalls Theodore Eickhoff of the University of Colorado Health Sciences Center, “but public-health officials were left without a vaccineand, consequently, a more severe flu season.”

Worse, the viruses that pose the greatest threat might be hardest to grow in eggs. Thats because global pandemics like the one that killed over 50 million people between 1918 and 1920 are thought to occur when a bird influenza changes in a way that lets it cross the species barrier and infect humans. Since humans havent encountered the new virus before, they have little protective immunity. The deadly bird flu circulating in Asia in 1997 and 1998, for example, worried public-health officials because it spread to some people who handled birds and killed themalthough the bug never circulated among humans. But when scientists tried to make vaccine the old-fashioned way, the bird flu quickly killed the eggs.

1.The moon-landing is mentioned in the first paragraph to illustrate_____.

Atechnology cannot solve all of our human problems

Bprogress in vaccine research for influenza has lagged behind

Cgreat achievements have been made by men in exploring the unknown

Dthe development of vaccine production methods can not be stopped

2.What step is essential to the traditional production of flu vaccine?

AManufacturers implant the vaccine into ordered chicken eggs.

BScientists identify the exact strain soon after a flu pandemic starts.

CPublic health measures are taken as an important pandemic-fighting tool.

DViruses are deadened and made clean before being put into vaccine use.

3.The foremost reason why the egg-based method is defective lies in_____.

Athe complex process of vaccine productionBits potential threat to human being

Cthe low survival rate for new flu vaccinesDits contribution to the flu vaccine shortage

4.Which of the following is true according to the passage?

AFlu vaccines now mainly use egg-based technology.

BA bird influenza has once circulated among humans.

CSafety can be greatly improved with cell-culture vaccines.

DModern vaccine production methods are to replace egg-based methods.

5.In the authors view, the new vaccine production method seems to be_____.



答案: 1.B 2.D 3.C 4.A 5.D




(3)brewv.)酿制(啤酒),沏(茶),煮(咖啡);~ up酝酿;(常用于进行时)(不愉快的事)即将来临



(6)in the pipeline在准备中; 在完成中; 在进行中; (货物)运输中; 即将送递

(7)circulatev.)循环;传播,流传;传递,传阅(~ sth. to sb.)




(11)lead time 前置时间,指完成一个程序或作业所需要的一段时间。


现代技术已经把人类送上了月球,也破解了人类的基因组。但是当涉及到培养流感病毒生产疫苗时,令人难以置信的是科学家依然在使用可食用鸡蛋。自20世纪40 年代以来,疫苗的生产者已经在鸡蛋里培植了大批的病毒。但是,考虑到每年有约3万6千美国人死于流感,有意思的是我们的第一防线依然是被美国健康和人类服务部部长汤米?汤普森称作为“麻烦的陈旧的鸡蛋方法的生产”。但是,新的细胞生产技术已经投入使用,并且由于美国现在面临的流感疫苗的严重短缺而可能最终得到它们所需要的支持。虽然专家就生产疫苗的新方法能否阻止现在出现的这种短缺现象无法达成共识,但是可以肯定的是现有的系统有严重的缺陷。