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1、一、从鸡蛋中培养流感疫菌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 so
2、me 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 calls “the cumbersome and archaic egg-based production.” New cell-based technologies are in the pipeline, however, and may finally get the suppo
3、rt 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
4、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
5、summer, automated machines inject virus into eggs and later suck out the influenza-rich goop. Virus from the eggs innards 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
6、 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
7、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 fi
8、nd 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 p
9、ose 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 enc
10、ountered 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 scien
11、tists 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_. A technology cannot solve all of our human problems B progress in vaccine research for influenza has lagged behind C great achievements have
12、 been made by men in exploring the unknown D the development of vaccine production methods can not be stopped 2.What step is essential to the traditional production of flu vaccine? A Manufacturers implant the vaccine into ordered chicken eggs. B Scientists identify the exact strain soon after a flu
13、pandemic starts. C Public health measures are taken as an important pandemic-fighting tool. D Viruses are deadened and made clean before being put into vaccine use. 3.The foremost reason why the egg-based method is defective lies in_. A the complex process of vaccine production B its potential threa
14、t to human being C the low survival rate for new flu vaccines D its contribution to the flu vaccine shortage 4.Which of the following is true according to the passage? A Flu vaccines now mainly use egg-based technology. B A bird influenza has once circulated among humans.C Safety can be greatly impr
15、oved with cell-culture vaccines. D Modern vaccine production methods are to replace egg-based methods. 5.In the authors view, the new vaccine production method seems to be_. A remarkable B criticized C efficient D accepted 答案： 1.B 2.D 3.C 4.A 5.D 二、二、美私有化方案 The National Association of Securities Dea
16、lers is investigating whether some brokerage houses are inappropriately pushing individuals to borrow large sums on their houses to invest in the stock market. Can we persuade the association to investigate would-be privatizers of Social Security? For it is now apparent that the Bush administrations privatization proposal will amount to the same thing: borrow trillions, put the money in the stock m
