Surgical masks vs. N95 respirators for preventing influenza among health-care workersOctober 02, 2009Surgical masks appear to be no worse than, and nearly as effective as N95 respirators in preventing influenza in health care workers, according to a study released early online today by JAMA. The study was posted online ahead of print because of its public health implications. It will be published in the November 4 issue of JAMA. Influenza is the most important cause of medically attended acute respiratory illness worldwide and the authors write there is heightened concern this year because of the influenza pandemic due to the H1N1 virus. "Data about the effectiveness of the surgical mask compared with the N95 respirator for protecting health care workers against influenza are sparse," the authors provide as background information in the article. "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." Mark Loeb, M.D., M.Sc., from McMaster University, Hamilton, Ontario, Canada, and colleagues conducted a randomized controlled trial of 446 nurses in eight Ontario hospitals to compare the surgical mask with the N95 respirator in protecting health care workers against influenza. The nurses were randomized into two groups: 225 were assigned to receive surgical masks and 221 were assigned to receive the fitted N95 respirator which they were to wear when caring for patients with febrile (fever) respiratory illness. The primary outcome of the study was laboratory-confirmed influenza. Effectiveness of the surgical mask was assessed as non-inferiority of the surgical mask compared with the N95 respirator. Between September 23, 2008 and December 8, 2008, "influenza infection occurred in 50 nurses (23.6 percent) in the surgical mask group and in 48 (22.9 percent) in the N95 respirator group (absolute risk difference -0.73 percent)," indicating non-inferiority of the surgical mask the authors report. Even among those nurses who had an increased level of the circulating pandemic 2009 H1N1 influenza strain, non-inferiority was demonstrated between the surgical mask group and the N95 respirator group for the 2009 influenza A(H1N1). "Our data show that the incidence of laboratory-confirmed influenza was similar in nurses wearing the surgical mask and those wearing the N95 respirator. Surgical masks had an estimated efficacy within 1 percent of N95 respirators," the authors write. "That is, surgical masks appeared to be no worse, within a prespecified margin, than N95 respirators in preventing influenza." In conclusion the authors state: "Our findings apply to routine care in the health care setting. They should not be generalized to settings where there is a high risk for aerosolization, such as intubation or bronchoscopy, where use of an N95 respirator would be prudent. In routine health care settings, particularly where the availability of N95 respirators is limited, surgical masks appear to be non-inferior to N95 respirators for protecting health care workers against influenza." (JAMA. 2009;302[17]: (doi:10.1001/jama.2009.1466. Available online at www.jamamedia.org) Editor's Note: This study was supported by the Public Health Agency of Canada. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Respiratory Protection Against Influenza In an accompanying editorial, Arjun Srinivasan, M.D., from the Centers for Disease Control and Prevention (CDC), Atlanta, and Trish M. Perl, M.D., M.Sc., from the School of Medicine and Bloomberg School of Public Health, Johns Hopkins University, Baltimore, write: "The 2009 influenza A(H1N1) pandemic has revived debate about the role of respiratory protection in preventing the transmission of influenza to health care personnel." The "N95 particulate respirators protect wearers from small particles when appropriately designed and worn." The World Health Organization and Society for Healthcare Epidemiology of America recommend the use of medical masks for most patient care. The CDC and Institute of Medicine recommend the use of N95 respirators during care of patients infected with the H1N1 influenza. "That this study is, to our knowledge, the first and only published randomized trial assessing respiratory protection for preventing influenza transmission is a sad commentary on the state of research in this area. Uncovering the truth and identifying the most appropriate way to protect health care personnel will require that other investigators build on this study ...," they write. "Ultimately, accumulating a body of evidence on this topic will provide much-needed answers." JAMA and Archives Journals |
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| Related Influenza Current Events and Influenza News Articles Asthma a significant risk factor for complications in children with H1N1 A new study on pediatric H1N1 influenza admissions has found that asthma is a significant risk factor for severe disease in children with pandemic H1N1 compared with the seasonal flu. Preventing H1N1 spread to health care workers: Dilemma, debate and confusion A commentary in the December issue of The Lancet Infectious Diseases brings to light the gaps in knowledge on the transmission of a common pathogen - the influenza virus - and its impact on decisions about how best to protect health care workers. New culprit for viral infections among elderly -- an overactive immune response Researchers at Yale School of Medicine have found that exaggerated responses of the immune system explain why the elderly succumb to viral infections more readily than younger people. New research helps explain why bird flu has not caused a pandemic Bird flu viruses would have to make at least two simultaneous genetic mutations before they could be transmitted readily from human to human, according to research published today in PLoS ONE. Mechanical ventilation for patients with lung damage don't always work as planned As more Canadians are diagnosed with H1N1 influenza infection, some will be admitted to hospital. The most severely affected may be treated in the intensive care unit (ICU) and placed on a mechanical ventilator to help them breathe while they recover from the infection. Researchers mobilizing global resources to test new treatments for severe H1N1 infection An important, ground-breaking initiative is unfolding in the global critical care community in response to the H1N1 pandemic. Worksite wellness programs may reduce employee absenteeism Emory University Rollins School of Public Health researchers will present Nov. 11 on a range of topics at the American Public Health Association's annual meeting in Philadelphia, including a study that found reduced absenteeism among employees participating in a large-scale worksite wellness program. U.S. and European Experts Applaud Creation of New Transatlantic Task Force on Global Antibiotic Resistance Threat Experts on both sides of the Atlantic applaud President Barack Obama and Swedish Prime Minister Fredrik Reinfeldt, representing the European Union (EU) Presidency, for establishing a transatlantic task force to address antibiotic resistance, an urgent and growing problem that threatens patient safety and public health worldwide. Poll: Many parents, high-priority adults who tried to get H1N1 vaccine unable to get it A new national poll from Harvard School of Public Health (HSPH) researchers found that a majority of adults who tried to get the H1N1 vaccine for themselves or their children have been unable to do so. When should flu trigger a school shutdown? As flu season approaches, parents around the country are starting to face school closures. But how bad should an influenza outbreak be for a school to shut down? More Influenza Current Events and Influenza News Articles |
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