New Report Raises Question of Flu Viability in Respirable Particles, Addresses PPE Imperatives

The National Institute for Occupational Safety and Health (NIOSH) and the National Personal Protective Technology Laboratory (NPPTL) have released the Institute of Medicine (IOM) report, "Preventing Transmission of Pandemic Influenza and other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Personnel, Update 2010 (2011)." In 2007, NIOSH requested that the the IOM investigate the urgent need to address the lack of preparedness regarding effective PPE for use in an influenza pandemic. The resultant 2008 report is available at The 2011 report is provided as an update to assess progress achieved over the past three years. The report is available for download at no cost at:

The report's authors explain that in 2008, when the IOM published the report "Preparing for an Influenza Pandemic: Personal Protective Equipment for Healthcare Workers," the major influenza-related concern was avian influenza (H5N1). They note, "As novel H1N1 influenza A became a reality in 2009, the many unknowns about the virulence, spread, and nature of the virus raised to the forefront issues regarding personal protective equipment (PPE) for healthcare personnel. A major issue was the nature of respiratory protection required because much remains to be learned about the mechanisms of influenza transmission. This report comes at a time when controversies continue on issues related to PPE for healthcare personnel, while at the same time, new horizons in PPE research and attention to PPE innovations offer promise of improvements in healthcare worker safety. Keeping the research momentum going is critical because between pandemics, the focus of research efforts often moves to other issues and the nation remains underprepared."

The report acknowledges that researchers "still have much to learn about how influenza is transmitted from person to person, and one major question that arose during the H1N1 influenza pandemic was determining what types of PPEparticularly face masks or respiratorsare needed to protect healthcare personnel from disease transmission. Because the focus of research efforts often shifts to other health concerns between pandemics, continuing the research momentum is critical to ensure that the nation is prepared for the next influenza pandemic."

In light of the unanswered research questions following the 2009 H1N1 influenza pandemic, the National Personal Protective Technology Laboratory at NIOSH asked the IOM to assess the progress of PPE research and to identify future directions for PPE for healthcare personnel. While the IOM found that there are gaps and deficiencies in the research about PPE use in healthcare, there is sufficient knowledge to recom-mend a four-pronged strategy for effective PPE use:

- Deliberate planning and preparation at the leadership and organizational levels

- Comprehensive training for all personnel, including supervisors and managers

- Widespread and convenient availability of appropriate PPE devices

- Accountability at all levels of the organization

The IOM also offers several recommendations for continuing the momentum of PPE research that are detailed in the report and the report brief. The more scientists and researchers know about how to maximize the effectiveness of PPE and its use, the more prepared we will be for the next influenza pandemic.

The committee conducting the investigation into this issue identified a set of criteria as a starting point for decisions on PPE selection and use. They agreed that PPE for healthcare workers should:

- Reduce the risks of disease and injury to healthcare personnel

- Minimize negative interactions with or effects on patients and their families

- Be acceptable and usable by healthcare personnel in their daily tasks

- Be practical regarding issues of cost, time and training to use

- Be appropriate to the occupational risk being encountered

PPE-related issues are becoming critical especially in light of the ongoing debate about the nature of influenza transmission. As the report authors note, "Having recently been through the 2009-2010 experience with H1N1 influenza, the committee is well aware of the ongoing challenges and controversies surrounding PPE for healthcare personnel. At this time, it is particularly important to build on that experience and take the actions needed to address the research and policy questions that will allow the healthcare community to be better prepared for the next epidemic or pandemic. Experience has shown that relevant research on these issues wanes between pandemics, and not permitting that to happen this time is crucial to resolving the research questions and setting evidence-based policies in place."

The report's authors point to animal studies where the ferret and guinea pig models appear to be highly representative of humans in terms of their susceptibility to infection, the influenza viral strains that display a transmissible phenotype, and the kinetics with which transmission occurs. They note, "Experiments performed in both of these animal models suggest that transmission of influenza viruses can proceed by both droplet spray as well as aerosol routes, which would include respirable particles. Animal studies have also pointed to a number of environmental factors, including relative humidity and temperature that may influence transmission. Recent studies that employed environmental monitoring of air for influenza as well as others that examined the contamination of fomites and hands with H1N1 have provided insights on the potential for influenza virus contamination of the healthcare environment. Nonetheless, data on the viability of influenza and other respiratory viruses in air samples and on fomites in these settings are limited."

The report continues, "Mathematical models have been developed to better characterize the relative contribution of influenza transmission modes. Available, well-specified parameters for these models are limited because information is lacking on the viability of influenza in aerosols, salivary virus concentrations, the amount of virus in respirable and inspirable particles, and the quantity and persistence of viability on various fomites in the healthcare setting. Taken together, progress has been made in understanding the modes of transmission, but the relative contribution of the modes are still unclear. Much remains to be learned about the effectiveness of control measures to prevent transmission. Observational and controlled studies relevant to PPE use and transmission of influenza or other viral respiratory diseases are limited be-cause study protocols were not usually in place for 2009 H1N1 or for recent seasonal flu periods, and studies have not provided adequate power to answer questions regarding the effectiveness of using PPE in reducing or preventing disease transmission."

The report acknowledges the growth of the literature pertaining to recent experience and the challenges and successes in providing face masks, respirators, and other PPE to healthcare workers. As the report notes, "As lessons learned during that experience continue to add to the body of knowledge, incorporating this information into research, policy and practice efforts will be important. In the initial phases of an epidemic or pandemic, when there are many unknowns about the virus or agent, one of the challenges is to determine PPE policy and then to adapt those policies as information is gained on the severity, transmission, and nature of the disease with an emphasis on communicating the changes. Standards-setting, regulatory, training, and research efforts continue to move toward improved respiratory protection, and recent work has begun to focus on the specifics of how to tailor PPE devices and PPE training to address the specific needs of healthcare personnel."

The report seems to indicate that better information is needed about how to provide guidance on PPE and other precautions, especially since it varies depending on the mode of transmission of the pathogen. As the report authors explain, "The ultimate goal would be to have the definitive information that would match the appropriate type of PPE with the pathogen, its mode of transmission, the infectious dose, and its risk to healthcare personnel. In many cases in industrial settings, this level of specificity is available for chemical exposures, although other industrial settings with unknown or mixed exposures continue to pose challenges. Reaching that point for protecting healthcare personnel will require concerted research efforts."

Through advocating an integrated approach that addresses the full spectrum of research and translates research findings into improvements in the standards of healthcare practice, the report says this approach "ensures that basic science initiatives are fully explored while also addressing clinical needs and testing the results in real-world settings, with the expectation that adaptations along the way will be made and tested." What is needed, the report says, is a system that efficiently moves research into practice, depicting the translation of research from basic science through policy and regulatory research.

The report makes the following recommendations to advance research and transfer these into practice across the spectrum of research opportunities:

- Develop standardized terms and definitions: CDC and OSHA should develop standardized terms, definitions and appropriate classifications to describe transmission routes and aerodynamic diameter of particles associated with respiratory disease transmission, and should involve a consensus from the industrial hygiene, infectious disease and healthcare communities.

- Develop and implement a comprehensive research strategy to understand viral respiratory disease transmission: The National Institutes of Health, in collaboration with other research agencies and organizations, should develop and fund a comprehensive research strategy to improve the understanding of viral respiratory disease transmission, including examining the characteristics of influenza transmission, animal models, human challenge studies and intervention trials.

- Continue and expand research on PPE for healthcare personnel: NPPTL and other agencies, private-sector companies and other or-ganizations should continue to advance research in designing and evaluating the effectiveness of respirator protection for healthcare personnel and expand its research efforts to improve and evaluate the effectiveness of gloves, gowns, face shields, and face masks in preventing the transmission of influenza or other viral respiratory diseases. Areas of focused research needs include effectiveness in preventing fomite, droplet spray, or aerosol transmission; decontamination and reusability; comfort, fit, and usability; impact on task per-formance; and development of technologies specifically for healthcare personnel.

- Examine the effectiveness of face masks and face shields as PPE: NPPTL should investigate the effectiveness of face masks and face shields in preventing transmission of viral respiratory diseases.

- Improve fit-test methods and evaluate user seal checks: NPPTL should develop novel, simpler fit-test methods and evaluate the effec-tiveness of performing user seal checks on N95 respirators.

- Explore healthcare safety culture and work organization: NIOSH and other relevant agencies, such as the AHRQ, and professional organizations should conduct research to better understand the role of safety culture and other behavioral and organizational factors on PPE usage in healthcare settings.

- Identify and disseminate effective leadership and training strategies and other interventions to improve PPE Use: NIOSH and other relevant agencies and professional organizations should support intervention effectiveness research to assess strategies, including innovative participatory approaches to training, for healthcare and supervisory staff at all levels to improve PPE usage and other related outcomes across the range of healthcare settings. To identify best practices, efforts should be made to conduct observational studies of PPE use by healthcare personnel in different types of work settings; develop, implement, and evaluate comprehensive leadership and training strategies and interventions that go beyond simple knowledge-based training; design training interventions specifically for supervisory and managerial personnel in different types of healthcare settings; examine long-term practice change and safety culture implementation related to educational interventions; improve use and understanding of PPE by home and community healthcare personnel; and develop assessment tools and metrics that take a broader approach to PPE and acknowledge the interaction of worker, task, and environmental factors.

- Clarify PPE guidelines for outbreaks of novel viral respiratory infections: NIOSH, other divisions of the CDC, OSHA and other public health agencies should develop a coordinated process to make, announce, and revise consistent guidelines regarding the use of PPE to be worn by healthcare personnel during a verified sustained national/international outbreak of a novel viral respiratory infection. The agencies should tailor their guidance in a timely and coordinated manner as the virulence, contagiousness, and affected populations are further characterized.

- Standards and certification for face masks and face shields: NIOSH, OSHA and standards-development organizations should develop the standards and certification processes needed to assess the performance of face masks and face shields as PPE.

- Establish PPE regulations for healthcare personnel: The CDC, including NIOSH, and OSHA should develop and promulgate guidelines and regulations that are consistent regarding the use of PPE by healthcare personnel for influenza and other viral respiratory diseases.

The report's authors note, "While the optimist can seek comfort in the fact that progress has been made in the past several years, the pragmatist must wonder about the rate of progress (or lack thereof) on such a critical issue that potentially threatens the security and economic well-being of the nation and the world. The committee hopes that this review will jumpstart and strengthen improvements in PPE for healthcare personnel that could be relevant to a range of viral respiratory diseases."

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