预防流感,哪种口罩最有效
【英文原文】
Small-particle filters offered nurses no better protection against the flu than standard surgical masks, according a study in JAMA. While the filters, called N95 respirators, can catch a much wider range of airborne pathogens, they are more expensive and in much shorter supply than the masks — of great concern during a flu pandemic. While some public-health organizations have recommended respirators over masks, and other organizations masks over respirators, this was the first published randomized trial comparing their effectiveness in preventing influenza. The 446 Canadian nurses in the study were assigned to wear either masks or N95 respirators while treating patients with respiratory illness and signs of fever over a roughly three-month period. By the end, 23.6% of nurses who wore surgical masks had gotten the flu, compared with 22.9% of the nurses who wore N95 respirators — a statistically insignificant difference. Similarly, there was no significant difference in the rates of H1N1 influenza, or swine flu, between the two groups.
Caveat: The study did not evaluate other factors, such as hand hygiene, that have been shown to affect influenza transmission. Additionally, the researchers had only limited data regarding how often the nurses wore the protective devices to which they were assigned.
【中文译文】
《美国医学会杂志》(JAMA)的一项研究表明，与普通的外科口罩相比，微粒过滤口罩并不能更有效地帮助护士预防流感。尽管名为N95呼吸防护口罩的这种过滤口罩能够捕捉到更多的依靠空气传播的病原体，但它们的售价更高，而且与外科口罩相比供应量也大大不足──这在流感大爆发的情况下不免令人担 。有些公共卫生组织建议使用呼吸防护口罩，而有些组织则推荐外科口罩。《美国医学会杂志》的这一研究是比较两种口罩在预防流感方面有效性的第一份随机性的评估报告。在大约三个月的时间里，参与此项研究的446名加拿大护士在护理患有呼吸系统疾病和发烧症状的病人时被指派佩戴外科口罩或者是N95呼吸防护口罩。研究结果显示，佩戴外科口罩的护士中有23.6%患上了流感，而佩戴N95口罩的护士中有22.9%患上了流感──这一差别并不具有统计学上的意义。与此相似，在H1N1，也就是猪流感的传播病例中，两组护士也没有显著性差异。
提示：此项研究并未评估其他因素，比如说已经被证明能够影响流感传播的手部卫生。此外，在护士们口罩佩戴时间长短的问题上，研究人员也只获得了有限的数据。
