Drug Resistancet Fades Quickly in Key Aids2 Drug
International medical guidelines call for5 pregnant women with advanced HIV to get a combination of AIDS drugs including nevirapine to prevent passing their infection on to their newborns during delivery. But in poor countries, combinations have been expensive and nevirapine has often been Used al. one, since studies have shown that a single dose can cut the transmission rate in half.
The further out you get from that exposure to single dose nevirapine, the less detectable nevirapine resistance is6, said Shahin Lockman of the Harvard School of Public Health in Boston7. She says waiting period for women who get the single dose of nevirapine at delivery can be as short as six months. If they started nevirapine-based treatment six or more months after nevirapine exposure, their treatment response8 was just as good, and really quite high, compared to women who did not have the single dose of nevirapine, she added. However, the women who started nevirapine-based treatment within six months of that nevirapine exposure were much more likely to experience treatment failure.
I.ynne Mofenson is chief of research on child, adolescent, and maternal AIDS at the U. S. National Institute of Child Health and Human Development10. She says the finding supports a World Health Organization H recommendation restricting a single dose of nevirapine only to pregnant HIV-infected women who are healthy enough to wait six months after childbirth for more nevirapine-based therapy. Otherwise, they should get other drugs during labor. It shows the importance of screening women for treatment while they are pregnant and putting them on appropriate therapy while they are pregnant to avoid having to start them too soon after they received preventive therapy, she explained.
练习：
A It is a broad-spectrum antibiotic and kills all kinds of bacteria.
C It prevents the transmission of the AIDS virus and protects one from heart attack.
2. Why does HIV resistance against nevirapine build very quickly even when the drug is used alone just once?
B Because there may not be a susceptibility test before using the drug.
D Because there are too many mutations of HIV for nevirapine to deal with.
A She may start nevirapine-based treatment soon after her delivery.
C She has to wait at least six months after that nevirapine exposure.
4. We may learn from this passage that HIV resistance against nevirapine
B will last forever in a woman who took nevirapine.
D is a problem too difficult to be solved.
A negative
C uncertain
答案与题解：
2.C 第三段第一句说，即使单独使用nevirapine一次，HIV病毒也会很快产生对nevirapine的抗药性，原因就是没有其他药物可以杀死nevirapine还没有杀死的病毒颗粒，这正是C项的内容。
4.A 第一段第三句说到抗药性存在的时间并不长，第四段第二句又说等待的时间可以短至六个月，另外，文章的标题也说抗药性很快消失，可见A项是正确选项，其他各项文章均未提及。