【正确答案】 1、pre-exposure prophylaxis    

【答案解析】[解析] 本题定位信息是mother-to-child transmission 和 partner-to-partner transmission，从而锁定文章第八段。该段第二句提到Drugs for pre-exposure prophylaxis…prevent mother-to-child transmission…and using ARVs before exposure to HIV have the same effect in protecting partners。由此可知本题应填入pre-exposure prophylaxis。