Loeb Mark, Dafoe Nancy, Mahony James, John Michael, Sarabia Alicia, Glavin Verne, Webby Richard, Smieja Marek, Earn David J D, Chong Sylvia, Webb Ashley, Walter Stephen D
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
JAMA. 2009 Nov 4;302(17):1865-71. doi: 10.1001/jama.2009.1466. Epub 2009 Oct 1.
Data about the effectiveness of the surgical mask compared with the N95 respirator for protecting health care workers against influenza are sparse. Given the likelihood that N95 respirators will be in short supply during a pandemic and not available in many countries, knowing the effectiveness of the surgical mask is of public health importance.
To compare the surgical mask with the N95 respirator in protecting health care workers against influenza.
DESIGN, SETTING, AND PARTICIPANTS: Noninferiority randomized controlled trial of 446 nurses in emergency departments, medical units, and pediatric units in 8 tertiary care Ontario hospitals.
Assignment to either a fit-tested N95 respirator or a surgical mask when providing care to patients with febrile respiratory illness during the 2008-2009 influenza season.
The primary outcome was laboratory-confirmed influenza measured by polymerase chain reaction or a 4-fold rise in hemagglutinin titers. Effectiveness of the surgical mask was assessed as noninferiority of the surgical mask compared with the N95 respirator. The criterion for noninferiority was met if the lower limit of the 95% confidence interval (CI) for the reduction in incidence (N95 respirator minus surgical group) was greater than -9%.
Between September 23, 2008, and December 8, 2008, 478 nurses were assessed for eligibility and 446 nurses were enrolled and randomly assigned the intervention; 225 were allocated to receive surgical masks and 221 to N95 respirators. Influenza infection occurred in 50 nurses (23.6%) in the surgical mask group and in 48 (22.9%) in the N95 respirator group (absolute risk difference, -0.73%; 95% CI, -8.8% to 7.3%; P = .86), the lower confidence limit being inside the noninferiority limit of -9%.
Among nurses in Ontario tertiary care hospitals, use of a surgical mask compared with an N95 respirator resulted in noninferior rates of laboratory-confirmed influenza.
clinicaltrials.gov Identifier: NCT00756574
关于外科口罩与N95口罩相比对医护人员预防流感有效性的数据较少。鉴于在大流行期间N95口罩可能短缺且在许多国家无法获得，了解外科口罩的有效性具有公共卫生重要性。
比较外科口罩与N95口罩对医护人员预防流感的效果。
设计、地点和参与者：安大略省8家三级护理医院急诊科、内科病房和儿科病房的446名护士参与的非劣效性随机对照试验。
在2008 - 2009年流感季节为发热呼吸道疾病患者提供护理时，分配佩戴经过适配测试的N95口罩或外科口罩。
主要结局是通过聚合酶链反应检测确诊的流感或血凝素滴度升高4倍。外科口罩的有效性评估为与N95口罩相比的非劣效性。如果发病率降低（N95口罩组减去外科口罩组）的95%置信区间（CI）下限大于 -9%，则满足非劣效性标准。
2008年9月23日至2008年12月8日期间，478名护士接受了资格评估，446名护士被纳入并随机分配接受干预；225名被分配接受外科口罩组，221名被分配接受N95口罩组（绝对风险差异，-0.73%；95%CI，-8.8%至7.3%；P = 0.86），置信区间下限在 -9%的非劣效性界限内。
在安大略省三级护理医院的护士中，如果使用外科口罩与N95口罩相比，实验室确诊流感的发病率无劣效。
clinicaltrials.gov标识符：NCT00756574
