Among the viruses soapy hand washing flushes down the drain is the one that causes the common cold. Other removable viruses cause hepatitis A, acute gastroenteritis and a host of other illnesses. 

    A separate key finding was that waterless handwipes only removed roughly 50 percent of bacteria from volunteer subjects?hands. 

    "We studied the efficacy of 14 different hand hygiene agents in reducing bacteria and viruses from the hands," said Emily E. Sickbert-Bennett, a public health epidemiologist with the University of North Carolina Health Care System and the UNC School of Public Health. "No other studies have measured the effectiveness in removing both bacteria and viruses at the same time." 

    For the first time, too, the UNC researchers tested what happened when people cleaned their hands for only 10 seconds, Sickbert-Bennett said. That represented the average length of time researchers observed busy health-care personnel washing or otherwise disinfecting their hands at work. 

    "Previous studies have had people clean their hands for 30 seconds or so, but that’s not what health-care workers usually do in practice, and we wanted to test the products under realistic conditions," she said. 

    Anti-microbial agents were best at reducing bacteria on hands, but waterless, alcohol-based agents had variable and sometimes poor effects, becoming less effective after multiple washes, Sickbert-Bennett said. For removing viruses from the hands, physical removal with soap and water was most effective since some viruses are hardy and relatively resistant to disinfection. 

    Researchers first had volunteers clean their hands and then contaminated their hands with Serratia marcescens and MS2 bacteriophage. Those are, respectively, a harmless bacterium and virus comparable to, and substituted for, disease-causing organisms. After that, scientists had the subjects clean their hands with various agents and measured how much of the bacteria and virus remained afterwards. 

    在一项比较各种手部清洁剂功效的大型综合性研究过程中，美国科学家发现，没有什么比传统的肥皂和清水更能有效地去除手上的细菌了。 

    据美国“每日科学”网站3月26日报道，研究证实，用肥皂洗手可将能引起普通感冒、甲型肝炎和急性肠胃炎等多种疾病的病毒有效地去除干净，研究同时发现不需水洗的手部清洗剂只能去除50%左右的手部细菌。 

    美国北卡罗来纳大学公共卫生流行病学家埃米丽-塞克伯特-博纳特说，我们分析了14种不同的手部清洁剂去除细菌和病毒的功效，而这是以前的研究不曾有过的。在研究过程中，科学家们对人们只用10秒时间洗手的效果进行了测试。这是在通常情况下，繁忙的医护卫生工作者平均所用的手部清洁以及消毒时间。共有62名志愿者参与了这项研究。

    志愿者把手洗干净后，研究人员在他们的手上涂上无害的粘质沙雷菌和MS2噬菌体，然后志愿者分别使用14种不同的手部清洁剂洗手，研究人员会分析最后残留在他们手上的细菌和病毒量。研究者发现，使用肥皂和清水洗手这种土办法，其除菌效果甚至要好于一些现代的清洁方法。研究显示，含抗菌成分的手部清洁产品在去除细菌这方面的效果要明显好于那些不需水洗的清洁剂；在去除病毒这方面，用肥皂和清水洗手的效果最好；而使用消毒湿巾擦拭的方法，消除病菌的效率最低。