A recent quote and post on GLP forums: Attention Health care workers: Why health care workers are being infected with Ebola despite protective gear Do the math: One of the highest risks for infection in Africa is health care workers despite protective gear but without a respirator. “Healthcare workers have experienced very high rates of morbidity and mortality in the past and current Ebola virus outbreaks. A facemask, or surgical mask, offers no or very minimal protection from infectious aerosol particles. As our examples illustrate, for a risk group 4 organism like Ebola, the minimum level of protection should be an N95 filtering facepiece respirator.” This type of respirator, however, would only be appropriate only when the likelihood of aerosol exposure is very low. For healthcare workers caring for many patients in an epidemic situation, this type of respirator may not provide an adequate level of protection. cidrap.umn.edu/news-perspective/2014/09/commentary-health-workers-need-optimal-respiratory-protection-ebola A Health care worker is infected by a case in Spain, despite protective gear. “The nurse has not been named. Spanish media said she is around 40 years old and only went into Viejos room twice — once to directly assist in his care, another time to clean his room after he died. On both occasions she was wearing special protective clothing.” usatoday/story/news/world/2014/10/07/spain-ebola-nurse-investigation/16844279/ A Health care worker is infected by the case in Dallas, despite protective gear: “She treated Duncan, the Ebola patient, after his second visit to the emergency room, on Sept. 28, and was “following full CDC precautions,” including wearing a gown, gloves, a mask and a protective face shield.” washingtonpost/news/post-nation/wp/2014/10/12/dallas-health-care-worker-who-treated-thomas-eric-duncan-has-tested-positive-for-ebola/ Do the math and you can only come to the same inescapable conclusion that these authors, (who are national experts on respiratory protection and infectious disease transmission) came to: In May they published a similar commentary on MERS-CoV. Dr Brosseau is a Professor and Dr Jones an Assistant Professor in the School of Public Health, Division of Environmental and Occupational Health Sciences, at the University of Illinois at Chicago. “Todays commentary was submitted to CIDRAP by the authors, who are national experts on respiratory protection and infectious disease transmission.” “We believe there is scientific and epidemiologic evidence that Ebola virus has the potential to be transmitted via infectious aerosol particles both near and at a distance from infected patients, which means that healthcare workers should be wearing respirators, not facemasks.1 The minimum level of protection in high-risk settings should be a respirator with an assigned protection factor greater than 10. A powered air-purifying respirator (PAPR) with a hood or helmet offers many advantages over an N95 filtering facepiece or similar respirator, being more protective, comfortable, and cost-effective in the long run. We strongly urge the US Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) to seek funds for the purchase and transport of PAPRs to all healthcare workers currently fighting the battle against Ebola throughout Africa—and beyond.. There has been a lot of on-line and published controversy about whether Ebola virus can be transmitted via aerosols. Most scientific and medical personnel, along with public health organizations, have been unequivocal in their statements that Ebola can be transmitted only by direct contact with virus-laden fluids2,3 and that the only modes of transmission we should be concerned with are those termed droplet and contact. These statements are based on two lines of reasoning. The first is that no one located at a distance from an infected individual has contracted the disease, or the converse, every person infected has had (or must have had) direct contact with the body fluids of an infected person. This reflects an incorrect and outmoded understanding of infectious aerosols, which has been institutionalized in policies, language, culture, and approaches to infection control. We will address this below. Briefly, however, the important points are that virus-laden bodily fluids may be aerosolized and inhaled while a person is in proximity to an infectious person and that a wide range of particle sizes can be inhaled and deposited throughout the respiratory tract.” Medical and infection control professionals have relied for years on a paradigm for aerosol transmission of infectious diseases based on very outmoded research and an overly simplistic interpretation of the data. In the 1940s and 50s, William F. Wells and other aerobiologists employed now significantly out-of-date sampling methods (eg, settling plates) and very blunt analytic approaches (eg, cell culturing) to understand the movement of bacterial aerosols in healthcare and other settings. Their work, though groundbreaking at the time, provides a very incomplete picture. Early aerobiologists were not able to measure small particles near an infectious person and thus assumed such particles existed only far from the source. They concluded that organisms capable of aerosol transmission (termed airborne) can only do so at around 3 feet or more from the source. Because they thought that only larger particles would be present near the source, they believed people would be exposed only via large droplets on their face, eyes, or nose. Modern research, using more sensitive instruments and analytic methods, has shown that aerosols emitted from the respiratory tract contain a wide distribution of particle sizes—including many that are small enough to be inhaled.5,6 Thus, both small and large particles will be present near an infectious person. Its time to abandon the old paradigm of three mutually exclusive transmission routes for a new one that considers the full range of particle sizes both near and far from a source. In addition, we need to factor in other important features of infectivity, such as the ability of a pathogen to remain viable in air at room temperature and humidity and the likelihood that systemic disease can result from deposition of infectious particles in the respiratory system or their transfer to the gastrointestinal tract. We recommend using aerosol transmissible rather than the outmoded terms droplet or airborne to describe pathogens that can transmit disease via infectious particles suspended in air. The potential for transmission via inhalation of aerosols, therefore, cannot be ruled out by the observed risk factors or our knowledge of the infection process. Many body fluids, such as vomit, diarrhea, blood, and saliva, are capable of creating inhalable aerosol particles in the immediate vicinity of an infected person. Cough was identified among some cases in a 1995 outbreak in Kikwit, Democratic Republic of the Congo,11 and coughs are known to emit viruses in respirable particles.17 The act of vomiting produces an aerosol and has been implicated in airborne transmission of gastrointestinal viruses.18,19 Regarding diarrhea, even when contained by toilets, toilet flushing emits a pathogen-laden aerosol that disperses in the air.20-22 “Experimental work has shown that Marburg and Ebola viruses can be isolated from sera and tissue culture medium at room temperature for up to 46 days, but at room temperature no virus was recovered from glass, metal, or plastic surfaces.23 Aerosolized (1-3 mcm) Marburg, Ebola, and Reston viruses, at 50% to 55% relative humidity and 72°F, had biological decay rates of 3.04%, 3.06%. and 1.55% per minute, respectively. These rates indicate that 99% loss in aerosol infectivity would occur in 93, 104, and 162 minutes, respectively.23 In still air, 3-mcm particles can take up to an hour to settle. With air currents, these and smaller particles can be transported considerable distances before they are deposited on a surface. There is also some experimental evidence that Ebola and other filoviruses can be transmitted by the aerosol route. Jaax et al24 reported the unexpected death of two rhesus monkeys housed approximately 3 meters from monkeys infected with Ebola virus, concluding that respiratory or eye exposure to aerosols was the only possible explanation. Zaire Ebola viruses have also been transmitted in the absence of direct contact among pigs 25 and from pigs to non-human primates,26 which experienced lung involvement in infection. Persons with no known direct contact with Ebola virus disease patients or their bodily fluids have become infected.12” “Facemasks, however, do not offer protection against inhalation of small infectious aerosols, because they lack adequate filters and do not fit tightly against the face.1 Therefore, a higher level of protection is necessary.” cidrap.umn.edu/news-perspective/2014/09/commentary-health-workers-need-optimal-respiratory-protection-ebola “To summarize, for the following reasons we believe that Ebola could be an opportunistic aerosol-transmissible disease requiring adequate respiratory protection: • Patients and procedures generate aerosols, and Ebola virus remains viable in aerosols for up to 90 minutes. • All sizes of aerosol particles are easily inhaled both near to and far from the patient. • Crowding, limited air exchange, and close interactions with patients all contribute to the probability that healthcare workers will be exposed to high concentrations of very toxic infectious aerosols. • Ebola targets immune response cells found in all epithelial tissues, including in the respiratory and gastrointestinal system. • Experimental data support aerosols as a mode of disease transmission in non-human primates. Risk level and working conditions suggest that a PAPR will be more protective, cost-effective, and comfortable than an N95 filtering facepiece respirator.” My opinion: Unless we are being given this protection, (PAPR (A powered air-purifying respirator) with a full facepiece (APF = 50) or a hood or helmet) we are unnecessarily placing ourselves and many others in harm’s way. Just my opinion for what it’s worth, but on a very serious issue, and I think that it is time for health care workers (and others) to stand up and be heard on this issue. hf It is time to stop blaming healthcare workers for getting infected, and look honesty at the whole picture and what has NOT BEEN WORKING and why it has not been working!!!
Posted on: Mon, 13 Oct 2014 06:56:14 +0000
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