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  3. Influenza and Vaccines There is no specific cure for influenza. Recommended treatment usually consists of bed rest and incre

Influenza and Vaccines There is no specific cure for influenza. Recommended treatment usually consists of bed rest and incre

admin2012-01-14  58
问题                      Influenza and Vaccines
    There is no specific cure for influenza. Recommended treatment usually consists of bed rest and increased intake of nonalcoholic fluids until fever and other symptoms lessen in severity. Certain drugs have been found effective in lessening flu symptoms, but medical efforts aimed against the disease focus chiefly on prevention by means of vaccines that create immunity.   No drugs can cure influenza, but certain antiviral medicines can relieve flu symptoms. Available by prescription, these drugs provide modest relief, but only if taken on the first or second day of symptoms. The drugs amantadine (sold under the brand name Symmetrel) and rimantadine (Flumadine), both in pill form, work against hemagglutinin and are effective in treating type A influenza. Two other drugs inhibit neuraminidase and are effective against both type A and type B strains: oseltamivir (Tamiflu) is in pill form and zanamivir (Relenza) is an inhalant.   A flu vaccine consists of greatly weakened or dead flu viruses, or fragments of dead viruses. Antigens in the vaccine stimulate the patient’s immune system to produce antibodies against the viruses. If the flu viruses invade a vaccinated person at a later time, the sensitized immune system recognizes the antigens, produces the antibodies and quickly responds to help destroy them.   About 5 to 10 percent of people who receive a flu vaccine experience mild, temporary side effects, typically soreness at the injection site. Young children who have not previously been exposed to the influenza virus are most likely to experience side effects.   Flu viruses constantly change so different virus strains must be incorporated in vaccines from one year to the next. Scientists try to provide a good match between the vaccine and the most serious virus strains circulating at the time. But because it takes months to manufacture and distribute vaccines, decisions on their composition must be made well before the start of each flu season. Each February experts at the World Health Organization (WHO) recommend a vaccine composition to be used for the forthcoming winter in the Northern Hemisphere; a second recommendation is made in September for vaccines to be used in the Southern Hemisphere. Typically vaccines contain antigens from three virus strains, usually two strains from type A and one strain from type B.   According to the CDC, the success of flu vaccines varies from one person to another. In healthy young adults, the vaccines are 70 to 90 percent effective in preventing the disease. In the elderly and people with certain chronic medical conditions, the vaccines are less effective in preventing illness but help reduce the severity of an infection and the risk of major complications or death. Studies show that flu vaccines reduce flu-related hospitalization by about 70 percent and flu-related deaths by about 85 percent among elderly people.   The CDC recommends annual flu shots for people who are at high risk for developing serious complications as a result of an influenza infection.
(A) [■]This group includes all people aged 65 and older; people in nursing homes and other facilities that house people with chronic medical conditions; people with chronic heart, lung or kidney disease, diabetes, an impaired immune system, or severe forms of anemia; children and adolescents with conditions treated for long periods of time with aspirin (which makes them vulnerable to Reye’s syndrome) ; and women who will be in the second or third trimester of pregnancy during the influenza season.
(B) [■] Some doctors encourage individuals who travel to areas of the world where influenza viruses circulate to receive the most current vaccine.
(C) [■] Vaccination taken earlier can better protect the travellers from being infected by influenza in the epidemic areas
(D) [■] vaccination is more urgently needed particularly if they are at higher risk of complications   It takes the human immune system one to two weeks after vaccination to develop antibodies to the flu antigens. According to the CDC, the best time to get flu shots in the United States is between October 1st and mid-November—sufficiently in advance of the peak of influenza activity, which in the United States generally lasts from late December until early March.   Flu shots must be given annually for two reasons. First, antibody protection that is provided by the vaccine decreases during the year following vaccination. Second, vaccines created for pre-existing viral strains may not work against new strains; nor does an infection with one flu strain confer immunity to infection by another strain.
An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.   Vaccination is a very important means of creating immunity to prevent the infection of flu. Answer Choices
A. Drugs can help lessen the symptoms of influenza and are more effective and convenient than vaccines.   
B. Despite possible mild side effects, vaccines can help destroy flu viruses with antigens stimulating immune systems to produce antibodies.   
C. Flu viruses change very frequently, so vaccines must also be adjusted every year, but vaccines are effective to different extents for different people.   
D. The best time to get flu shots is between October 1st and mid-November because it takes time for vaccination to take effect.   
E. The Northern Hemisphere and the Southern Hemisphere have different periods of time to manufacture and distribute vaccines.   
F. Certain groups of people are strongly recommended for vaccination and flu shots are better to be given every year at appropriate times.
选项
答案B. Despite possible mild side effects, vaccines can help destroy flu viruses with antigens stimulating immune systems to produce antibodies. C. Flu viruses change very frequently, so vaccines must also be adjusted every year, but vaccines are effective to different extents for different people. F. Certain groups of people are strongly recommended for vaccination and flu shots are better to be given every year at appropriate times.
解析 本题为篇章总结题，考查考生理解全篇中心思想和相关重要信息的能力，考生通过区分主要观点和次要观点以及文章中没有提及的观点达到总结全篇的目的。本文是对流感防治的介绍，主要内容是围绕注射疫苗展开的。选项B、C、F概括了全文的主要思想，即虽然可能有轻微的副作用，疫苗可以通过抗原刺激人体产生抗体，从而能够帮助预防流感；流感病毒不断改变，因此疫苗也必须随之改变成分，但是疫苗对不同人群的有效性不同；CDC组织和医生建议一些人群注射疫苗，而且疫苗应该每年注射。选项A、D、E所含的信息要么错误，要么 是细枝末节，不能概括全文的主要意思。
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