And in recent years, that's brought two key groups of investors to the market.

近年来，这已经吸引了两类重要的投资者进入市场。

African Americans are a key risk group. They make up 12 percent of the population, yet they account for more than 50 percent of new HIV infections.

非裔美国人是个很危险的群体，他们占总人数的12%，但却占艾滋病新感染人数的50%以上。

Officials say hidden transmission sources in communities still exist and Beijing will use antigen testing as a supplementary measure to screen key risk groups and staff in key industries.

官方表示，社区中面依然存在隐匿传染源，北京将把抗原检测作为一项补充措施，对重点风险人群和重点行业的工作人员进行筛查。