一本教会你“做对”题的6级阅读书 day15 passage4
Passage 4 The Long-Term Evidence for Vaccines
流感与疫苗 《新闻周刊》
[00:00]With some reports saying that the worst of the H1N1 outbreak may have already come
[00:09]and gone this flu season in North America but not worldwide,
[00:14]parents who decided to sit out vaccinations for their children may feel validated.
[00:22]But not only is that strategy risky, it's uninformed,
[00:27]and ignores a larger truth about the benefit of vaccines.
[00:33]Throughout North America and Europe,
[00:36]an anti-vaccination movement has steadily grown over the past two decades,
[00:42]and was recently jet-propelled amid anxiety over immunizing pregnant women
[00:49]and children against the H1N1 "swine flu."
[00:55]If a woman is exposed to influenza while pregnant,
[01:00]or if an unvaccinated child gets the flu in his or her first year of life,
[01:07]the baby's developing brain may be severely damaged by the virus.
[01:13]Analysis of medical records of Americans who were born in the late '50s
[01:20]and early '60s shows that having the mother catch the flu while pregnant
[01:27]increased the chance her child would later develop schizophrenia.
[01:33]It's not a trivial difference: the children of moms
[01:37]who had flu midway during their pregnancies were as much as eight times
[01:43]more likely to become schizophrenic.
[01:47]Overall, prenatal and infant exposure to influenza is strongly
[01:54]associated with cognitive failures.
[01:58]Babies are born with brains and immune systems that are still developing,
[02:04]and will not be hard-wired and strong until their second year of life.
[02:10]Scientists are increasingly discovering links
[02:15]between viral infections during those precious times,
[02:19]and psychiatric problems ranging from lifelong depression to acute learning deficits.
[02:27]In infancy infection with chickenpox doubles the risk of cerebral palsy,
[02:34]according to Australian researchers.
[02:37]Having rubella during pregnancy increases
[02:41]by 80 percent the chances of severe birth defects in that mother's child,
[02:47]including small brains and hearts, blindness, deafness, and severe learning deficits.
[02:56]Children who contract measles, chickenpox,
[03:00]or whooping cough can develop encephalitis
[03:05]or meningitis-infections of the central nervous system-which can cause epilepsy,
[03:11]brain damage, and death. Parents cannot protect their children's brains
[03:18]against everything, but the basic battery of vaccines
[03:23]can block the bulk of these viral insults.
[03:27]And the good news is that the still-developing immune system of babies
[03:33]and infants is ripe for the vaccine-induced programming
[03:38]that can confer decades-in some cases, lifelong-protection.
[03:45]Other vaccine-preventable diseases-measles, rubella, mumps,
[03:51]chickenpox, and whooping cough-can damage the optic nerves
[03:57]and hearing of fetuses and newborns. The effect in these cases is immediate and obvious.
