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. 

    在一項比較各種手部清潔劑功效的大型綜合性研究過程中，美國科學家發現，沒有什么比傳統的肥皂和清水更能有效地去除手上的細菌了。 

    據美國“每日科學”網站3月26日報道，研究證實，用肥皂洗手可將能引起普通感冒、甲型肝炎和急性腸胃炎等多種疾病的病毒有效地去除干凈，研究同時發現不需水洗的手部清洗劑只能去除50%左右的手部細菌。 

    美國北卡羅來納大學公共衛生流行病學家埃米麗-塞克伯特-博納特說，我們分析了14種不同的手部清潔劑去除細菌和病毒的功效，而這是以前的研究不曾有過的。在研究過程中，科學家們對人們只用10秒時間洗手的效果進行了測試。這是在通常情況下，繁忙的醫護衛生工作者平均所用的手部清潔以及消毒時間。共有62名志愿者參與了這項研究。

    志愿者把手洗干凈后，研究人員在他們的手上涂上無害的粘質沙雷菌和MS2噬菌體，然后志愿者分別使用14種不同的手部清潔劑洗手，研究人員會分析最后殘留在他們手上的細菌和病毒量。研究者發現，使用肥皂和清水洗手這種土辦法，其除菌效果甚至要好于一些現代的清潔方法。研究顯示，含抗菌成分的手部清潔產品在去除細菌這方面的效果要明顯好于那些不需水洗的清潔劑；在去除病毒這方面，用肥皂和清水洗手的效果最好；而使用消毒濕巾擦拭的方法，消除病菌的效率最低。