题型:阅读理解 题类:模拟题 难易度:普通
浙江省宁波市20182019学年高三英语5月模拟测试卷(含小段音频)
A single dose(剂量) of an experimental vaccine(疫苗) can protect mice against the Zika(寨卡) virus, raising renewed hope of a vaccine for humans, say scientists. The US team say the results, published in Nature, are "striking" and should encourage research efforts.
Tests in humans could begin in months. But even if these go well, a licensed vaccine for widespread use to protect those at most risk such as pregnant women would still be years away, experts advise. Zika has been spreading across Central and South America and, most recently, Africa. More than 60 countries and territories now have continuing transmission(传播) of the disease, which is carried by mosquitoes. The virus causes serious birth damages during pregnancy and has been declared a global public health emergency.
Now, developing a vaccine for pregnant women to protect their unborn babies is an international research priority(优先事项). US scientists from the Walter Reed Army Institute of Research, the Beth Israel Deaconess Medical Center and Harvard Medical School tested two types of Zika vaccine in mice – one based on bits of genetic(基因的) code from the virus and another that is an inactive (and therefore harmless) copy of Zika. Both worked well, protecting every mouse that was immunised against the virus. In comparison, all of the mice not given the vaccine caught Zika after they were exposed to it.
Researchers say they will push ahead with developing the needed virus vaccine. There are many existing vaccines for other disease that use this type of technology, while there are relatively few DNAbased vaccines. Of course, future tests will need to check the vaccine is safe and effective in humans, as well as how long the immunity might last.
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