首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Modern technology has put men on the moon and deciphered the human genome. But when it comes to brewing up flu to make vaccines
Modern technology has put men on the moon and deciphered the human genome. But when it comes to brewing up flu to make vaccines
admin
2021-12-15
36
问题
Modern technology has put men on the moon and deciphered the human genome. But when it comes to brewing up flu to make vaccines (疫苗), science still turns to the incredible edible egg. Ever since the 1940s, vaccine makers have grown large batches of virus inside chicken eggs. New cell-based technologies are in the pipeline, 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 strains—two influenza A strains and one B strain—for 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 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 main reason is that it’s 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 it’s 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.
What’s more, some flu strains don’t 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 couldn’t 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 vaccine—and, consequently, a more severe flu season. "
Worse, the viruses that pose the greatest threat might be hardest to grow in eggs. That’s 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 haven’t 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 them—although the bug never circulated among humans. But when scientists tried to make vaccine the old-fashioned way, the bird flu quickly killed the eggs.
Which of the following statements is TRUE according to the passage?
选项
A、Flu vaccines now mainly use egg-based technology.
B、A bird influenza has once been circulated among humans.
C、Safety can be greatly improved by cell-cultured vaccines.
D、Modern vaccine production methods are to replace egg-based medthods.
答案
A
解析
由题干中的the passage及各选项语义定位至第一段前两句。细节辨认题。定位句表明了作者对依然使用鸡蛋生产流感疫苗感到难以置信,由此可知,现在生产疫苗主要还是采用鸡蛋培育法,因此A)正确。
转载请注明原文地址:https://kaotiyun.com/show/6Dx7777K
0
大学英语六级
相关试题推荐
A、Clearerroadsigns.B、Morepeopledrivingsafely.C、Strictertrafficrules.D、Moreself-drivingtrucksontheroad.B细节推断题。女士在
A、Theyarebothworriedaboutthenegativeimpactoftechnology.B、Theydiffergreatlyintheirknowledgeofmoderntechnology.
A、Herpreviousdebthadn’tbeenclearedyet.B、Hercredithistorywasconsideredpoor.C、Shehadapparentlyaskedfortoomuch.
A、Payadebtlongoverdue.B、Buyapieceofproperty.C、Startherownbusiness.D、Checkhercredithistory.C事实细节题。对话中提到,银行因担心女士
A、Theirappreciationofhelpfromtheoutsiders.B、Theirsenseofsharingandcaring.C、Theirreadinesstoadapttotechnology.
PresidentObamahasbeentakingsomeheatintechnologycirclesovercommentshemadeatacommencementaddressovertheweekend
PresidentObamahasbeentakingsomeheatintechnologycirclesovercommentshemadeatacommencementaddressovertheweekend
A、Difficultbutrewarding.B、Variedandinteresting.C、Time-consumingandtiring.D、Demandingandfrustrating.B根据上题,考生可推测选项使用形容
A、Itrequirestoomuchtravelingtodifferentcities.B、Itlimitsinteractionamongstudents.C、Itwillincreaseclasssize.D、I
A、Bysendingfewerdiscstothevoters.B、Byresortingtothelawsandregulations.C、Byusingstrongeranti-piracytechnology.
随机试题
国际教育
非洲开发银行成立于____________。
根据美国管理学家哈罗德.孔茨的观点,有效决策的判断标准是()。
男,55岁,四肢麻木沉重半年,走路不稳,双脚有踩棉感,伴有右上肢疼痛,运动不灵活。入院后体格检查:颈椎生理前凸消失,C4~C6叩痛,向右上肢放射,双下肢肌力为Ⅳ~Ⅴ级,肌张力高,双侧膝反射亢进,双踝阵挛阳性。如果诊断为脊髓型颈椎病,最佳治疗方法是
A、吸附色谱B、离子交换色谱C、聚酰胺色谱D、正相分配色谱E、凝胶色谱分离分子量不同的化合物可采用
工期索赔是()提出的单向索赔。
票据债务人以外的人,为担保特定债务人履行票据债务而在票据上记载有关事项并盖章的行为称为()。
AlthoughweallspeakEnglish,Idon’toften______him.
Generouspublicfundingofbasicsciencewould______considerablebenefitsforthecountry’shealth,wealthandsecurity.
Accordingtothepassage,rickshawsareused,inKolkatamainlyforthefollowingpurposesEXPECT______.Wecaninferfromthe
最新回复
(
0
)