Scientistshaveknownfordecadesthathavingmeasles(麻疹)suppr...

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Scientists have known for decades that having measles (麻疹) suppresses kids’ immune systems for several weeks or months, leaving them ill-equipped to fight off pneumonia, bronchitis and other infections.

Now a team of researchers has suggested that the measles virus may also leave a longer-lasting sort of “immune-amnesia” that makes it harder for people to stave off other illnesses for two years or more.

That re-emphasizes the importance of vaccination (疫苗), said biologist Michael Mina, lead author of a paper that was published in the journal Science.

“There may be a long-lasting impact that you can’t undo if your child gets measles,” he said. “I hope this study can impress upon people the danger measles poses.”

The researchers used what Mina called “an unconventional approach” to search for the long-lasting immune system effects. Previous work in monkeys suggested that monkeys with the disease lost white blood cells their bodies had trained to fight off other illnesses, leaving them more likely to be infected.

To test if a similar thing may occur in humans, the group mined historical data to find out the relationship between measles incidence (发病率) and deaths from other infectious diseases.

They turned to data from England and Wales — developed nations where disease levels are generally low, allowing a less-confused view of measles’ effects. Studying measles incidence and deaths from infectious disease both before and after the introduction of the measles vaccine in the U.K. in the 1960s, Mina and the team saw a sort of shadow effect, where deaths from a variety of non-measles infectious diseases closely tracked measles incidence. The more measles in a population, the more deaths from other illnesses in the 28-month period that followed.

“Really it didn’t matter what age group, what decade or what country,” said Mina. “They all showed consistent results … what we’re suggesting happens over the long term is that your immune system works fine, but it has forgotten what it previously learned.”

Some researchers who were not involved in the work questioned whether the reductions in deaths as measles cases declined may have had more to do with improving nutrition and smaller family size than with prolonged immune suppression.

Others thought the paper’s opinion of years-long suppression was seemingly reasonable but said they could not comment on the mathematical models the group used.

To know for certain what was behind the effect the group saw, Mina agreed, scientists would need to look at immune cells and observe their behavior. He said he would like to push the work in a more traditional direction: back into the laboratory.

62. Why did Mina call their research method “an unconventional approach”?

A. Their research was based on the historical data.

B. Their research compared monkeys with humans.

C. They only paid attention to developed nations.

D. They discovered a sort of shadow effect.

63. According to Mina, what is the significance of their research?

A. They warned people that measles can result in other infectious diseases.

B. They carried out the research on measles in an unconventional approach.

C. They showed how dangerous measles is and the importance of vaccination.

D. They found out the disease levels are generally low in developed nations..

64. The underlined phrase “stave off” in Paragraph 2 is closest in meaning to ________.

A. keep away B. survive from C. search for D. turn down