Información: 239 científicos ponen en duda el supuesto ‎modo de transmisión del Covid-19‎

 

INFORMACION… ARGOSIS: JULIO 08 DE 2020…

 

xRevista ‎especializada ‘Clinical Infectious Diseases’

Estados Unidos

Red Voltaire

 

Desde el inicio de la epidemia de Covid-19 se ha dado por sentado que este virus se transmite ‎a través de las proyecciones de saliva y de las vías respiratorias que pueden quedar en el aire o en ‎las superficies, además de por contacto. Partiendo de ese principio, se aconsejó limpiar ‎frecuentemente puertas, mesas u otras superficies que tocamos, portar mascarillas de protección ‎y mantener cierta distancia entre las personas. ‎

 

Pero en realidad no está demostrado que el Covid-19 se transmita de esa manera. ‎

 

Por el contrario, si se considera el Covid-19 como un virus respiratorio sería más lógico pensar que ‎se transmite únicamente como las demás enfermedades virales respiratorias. En ese caso, es ‎absurdo dedicarse sacar brillo a los pomos de las puertas, es inútil el uso de ‎máscaras sanitarias o de trajes aislantes y es ridícula la imposición de medidas como el llamado ‎‎“distanciamiento social”. El único modo de prevención realmente eficaz sería ventilar adecuadamente los espacios cerrados. ‎

 

Aunque tampoco está demostrado ese modo de transmisión, esta última medida de prevención es ‎mucho más lógica que las anteriores. ‎

 

Numerosos investigadores sostienen esta teoría desde que se inició la epidemia, pero no se ‎les da la palabra. Fue la hipótesis de estos investigadores lo que llevó a Thierry Meyssan a ‎comentar con ironía, desde este sitio web, la obsesión por el uso de mascarillas sanitarias o ‎quirúrgicas, comparándola con las máscaras utilizadas en el siglo XVII, en tiempos de las ‎epidemias de peste [1].‎

 

De hecho, 239 científicos acaban de publicar una carta abierta en ese sentido en la revista ‎especializada Clinical Infectious Diseases.‎

 

Carta:

 

It is Time to Address Airborne Transmission of COVID-19

 

Lidia Morawska1,*, Donald K. Milton2

 

1 International Laboratory for Air Quality and Heath, WHO Collaborating Centre, Queensland University of Technology, 2 George Street, Brisbane, QLD 4001 Australia. Email: l.morawska@qut.edu.au

 

2 Institute for Applied Environmental Health, University of Maryland School of Public Health, 255 Campus Dr, College Park, Maryland, USA. Email: dmilton@umd.edu

 

Corresponding author: Lidia Morawska, Email: l.morawska@qut.edu.au

 

Keywords: airborne transmission; airborne infection spread; coronavirus; COVID-19; SARS-CoV-2 virus.

 

© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons AttributionNonCommercial-NoDerivs licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com  

 

Commentary

 

We appeal to the medical community and to the relevant national and international bodies to recognize the potential for airborne spread of COVID-19. There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission.

 

Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 m from an infected individual (see e.g. [1-4]).

 

For example, at typical indoor air velocities [5], a 5 μm droplet will travel tens of meters, much greater than the scale of a typical room, while settling from a height of 1.5 m to the floor. Several retrospective studies conducted after the SARS-CoV-1 epidemic demonstrated that airborne transmission was the most likely mechanism explaining the spatial pattern of infections e.g. [6].

 

Retrospective analysis has shown the same for SARS-CoV-2 [7-10]. In particular, a study in their review of records from a Chinese restaurant, observed no evidence of direct or indirect contact between the three parties [10]. In their review of video records from the restaurant, they observed no evidence of direct or indirect contact between the three parties. Many studies conducted on the spread of other viruses, including respiratory syncytial virus (RSV) [11], Middle East Respiratory Syndrome coronavirus (MERS-CoV) [8], and influenza [2,4], show that viable airborne viruses can be exhaled [2] and/or detected in the indoor environment of infected patients [11-12].

 

This poses the risk that people sharing such environments can potentially inhale these viruses, resulting in infection and disease. There is every reason to expect that SARS-CoV-2 behaves similarly, and that transmission via airborne microdroplets [10,13] is an important pathway. Viral RNA associated with droplets smaller than 5 μm has been detected in air [14], and the virus has been shown to maintain infectivity in droplets of this size [9]. Other viruses have been shown to survive equally well, if not better, in aerosols compared to droplets on a surface [15].

 

The current guidance from numerous international and national bodies focuses on hand washing, maintaining social distancing, and droplet precautions. Most public health organizations, including the World Health Organization (WHO) [16], do not recognize airborne transmission except for aerosol-generating procedures performed in healthcare settings. Hand washing and social distancing are appropriate, but in our view, insufficient to provide protection from virus-carrying respiratory microdroplets released into the air by infected people. This problem is especially acute in indoor or enclosed environments, particularly those that are crowded and have inadequate ventilation [17] relative to the number of occupants and extended exposure periods (as graphically depicted in Figure 1). For example, airborne transmission appears to be the only plausible explanation for several superspreading events investigated which occurred under such conditions e.g. [10], and others where recommended precautions related to direct droplet transmissions were followed. 

 

The evidence is admittedly incomplete for all the steps in COVID-19 microdroplet transmission, but it is similarly incomplete for the large droplet and fomite modes of transmission. The airborne transmission mechanism operates in parallel with the large droplet and fomite routes, e.g. [16] that are now the basis of guidance. Following the precautionary principle, we must address every potentially important pathway to slow the spread of COVID-19. The measures that should be taken to mitigate airborne transmission risk include:

 

 Provide sufficient and effective ventilation (supply clean outdoor air, minimize recirculating air) particularly in public buildings, workplace environments, schools, hospitals, and aged care homes.

 Supplement general ventilation with airborne infection controls such as local exhaust, high efficiency air filtration, and germicidal ultraviolet lights.

 Avoid overcrowding, particularly in public transport and public buildings.

 

Such measures are practical and often can be easily implemented; many are not costly. For example, simple steps such as opening both doors and windows can dramatically increase air flow rates in many buildings. For mechanical systems, organizations such as ASHRAE (the American Society of Heating, Ventilating, and Air-Conditioning Engineers) and REHVA (the Federation of European Heating, Ventilation and Air Conditioning Associations) have already provided guidelines based on the existing evidence of airborne transmission. The measures we propose offer more benefits than potential downsides, even if they can only be partially implemented.

 

Figure 1. Distribution of respiratory microdroplets in an indoor environment with (a) inadequate ventilation and (b) adequate ventilation.

 

It is understood that there is not as yet universal acceptance of airborne transmission of SARS-CoV2; but in our collective assessment there is more than enough supporting evidence so that the precautionary principle should apply. In order to control the pandemic, pending the availability of a vaccine, all routes of transmission must be interrupted.

 

We are concerned that the lack of recognition of the risk of airborne transmission of COVID-19 and the lack of clear recommendations on the control measures against the airborne virus will have significant consequences: people may think that they are fully protected by adhering to the current recommendations, but in fact, additional airborne interventions are needed for further reduction of infection risk.

 

This matter is of heightened significance now, when countries are re-opening following lockdowns - bringing people back to workplaces and students back to schools, colleges, and universities. We hope that our statement will raise awareness that airborne transmission of COVID-19 is a real risk and that control measures, as outlined above, must be added to the other precautions taken, to reduce the severity of the pandemic and save lives.

 

Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any agency/institution.

 

Acknowledgment

 

Together with the authors, 239 scientists support this Commentary, and their affiliations and contact details are listed in the Supplementary. 

 

The following scientists contributed to formulating this commentary: Linsey C. Marr, William Bahnfleth, Jose-Luis Jimenez, Yuguo Li, William W. Nazaroff, Catherine Noakes, Chandra Sekhar, Julian Wei-Tze Tang, Raymond Tellier, Philomena M. Bluyssen, Atze Boerstra, Giorgio Buonanno, Junji Cao, Stephanie J. Dancer, Francesco Franchimon, Charles Haworth, Jaap Hogeling, Christina Isaxon, Jarek Kurnitski, Marcel Loomans, Guy B. Marks, Livio Mazzarella, Arsen Krikor Melikov, Shelly Miller, Peter V. Nielsen, Jordan Peccia, Xavier Querol, Olli Seppänen, Shin-ichi Tanabe, Kwok Wai Tham, Pawel Wargocki, Aneta Wierzbicka, Maosheng Yao. 

 

The following scientists reviewed the document: Jonathan Abbatt, John Adgate, Alireza Afshari, KangHo Ahn, Francis Allard, Joseph Allen, Celia Alves, Meinrat O. Andreae, Isabella Annesi-Maesano, Ahmet Arısoy, Andrew P. Ault, Gwi-Nam Bae, Gabriel Bekö, Scott C. Bell, Allan Bertram, Mahmood Bhutta, Seweryn Bialasiewicz, Merete Bilde, Tami Bond, Joseph Brain, Marianna Brodach, David M. Broday, Guangyu Cao, Christopher D. Cappa, Annmarie Carlton, Paul K. S. Chan, Christopher Chao, Kuan-Fu Chen, Qi Chen, Qingyan Chen, David Cheong, Per Axcel Clausen, Ross Crawford, Derek Clements-Croome, Geo Clausen, Ian Clifton, Richard L. Corsi, Benjamin J. Cowling, Francesca Romana d'Ambrosio, Ghassan Dbaibo, Richard de Dear, Gianluigi de Gennaro, Peter DeCarlo, Philip Demokritou, Hugo Destaillats, Joanna Domagala-Kulawik, Neil M. Donahue, Caroline Duchaine, Marzenna R. Dudzinska, Dominic E. Dwyer, Greg Evans, Delphine K. Farmer, Kevin P. Fennelly, Richard Flagan, Janine Fröhlich-Nowoisky, Manuel Gameiro da Silva, Christian George, Marianne Glasius, Allen H. Goldstein, João Gomes, Michael Gormley, Rafal Górny, David Grimsrud, Keith Grimwood, Charles N. Haas, Fariborz Haghighat, Michael Hannigan, Roy Harrison, Ulla HaverinenShaughnessy, Philippa Howden-Chapman, Per Heiselberg, Daven K. Henze, Jean-Michel Heraud, Hartmut Herrmann, Philip K. Hopke, Ray Horstman, Wei Huang, Alex Huffman, David S. Hui, Tareq Hussein, Gabriel Isaacman-VanWertz, Jouni J.K. Jaakkola, Matti Jantunen, Lance Jennings, Dennis Johansson, Jan Kaczmarczyk, George Kallos, David Katoshevski, Frank Kelly, Søren Kjærgaard, Luke D. Knibbs, Henrik N. Knudsen, GwangPyo Ko, Evelyn S.C. Koay, Jen Kok, Nino Kuenzli, Markku Kulmala, Kazukiyo Kumagai, Prashant Kumar, Kazumichi Kuroda, Kiyoung Lee, Nelson Lee, Barry Lefer, Vincent Lemort, Xianting Li, Dusan Licina, Chao-Hsin Lin, Junjie Liu, Kam Lun E. Hon, John C. Little, Li Liu, Janet M. Macher, Ebba Malmqvist, Corinne Mandin, Ivo Martinac, Dainius Martuzevičius, Mark J. Mendell, David Miller, Claudia Mohr, Luisa T. Molina, Glenn Morrison, Roya Mortazavi, Edward Nardell, Athanasios Nenes, Mark Nicas, Zhi Ning, Jianlei Niu, Hidekazu Nishimura, Colin O'Dowd, Bjarne W. Olesen, Paula J. Olsiewski, Spyros Pandis, Daniel Peckham, Tuukka Petäjä, Zbigniew Popiolek, Ulrich Pöschl, Wayne R. Ott, Kimberly Prather, Andre S. H. Prevot, Hua Qian, Shanna Ratnesar-Shumate, James L. Repace, Tiina Reponen, Ilona Riipinen, Susan Roaf, Allen L. Robinson, Yinon Rudich, Manuel Ruiz de Adana, Masayuki Saijo, Reiko Saito, Paulo Saldiva, Tunga Salthammer, Joshua L. Santarpia, John H. Seinfeld, Gary S. Settles, Siegfried Schobesberger, Paul T. J. Scheepers, Max H. Sherman, Alan Shihadeh, Manabu Shiraiwa, Jeffrey Siegel, Torben Sigsgaard, Brett C. Singer, James N. Smith, Armin Sorooshian, Jerzy Sowa, Brent Stephens, Huey-Jen Jenny Su, Jordi Sunyer, Jason D. Surratt, Kazuo Takahashi, Nobuyuki Takegawa, Jørn Toftum, Margaret A. Tolbert, Euan Tovey, Barbara J. Turpin, Annele Virtanen, John Volckens, Claire Wainwright, Lance A. Wallace, Boguang Wang, Chia C. Wang, Michael Waring, John Wenger, Charles J. Weschler, Brent Williams, Mary E. Wilson, Armin Wisthaler, Kazimierz Wojtas, Douglas R. Worsnop, Ying Xu, Naomichi Yamamoto, Xudong Yang, Hui-Ling Yen, Hiroshi Yoshino, Hassan Zaraket, Zhiqiang (John) Zhai, Junfeng (Jim) Zhang, Qi Zhang, Jensen Zhang, Yinping Zhang, Bin Zhao, Tong Zhu.

 

References:

 

1 Morawska, L. et al. Size distribution and sites of origin of droplets expelled from the human respiratory tract during expiratory activities. Journal of Aerosol Science 2009; 40: 256-269.

 

2 Yan J, Grantham M, Pantelic J, et al. Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community. Proceedings of the National Academy of Sciences of the United States of America USA, 2018; 115: 1081–6.

 

3 Xie, X., Li, Y., Chwang, A., Ho, P. & Seto, W. How far droplets can move in indoor environments-revisiting the Wells evaporation-falling curve. Indoor Air, 2007; 17: 211-225.

 

4 Lindsley, W.G. et al. Viable influenza A virus in airborne particles from human coughs. Journal of Occupational and Environmental Hygiene, 2015; 12: 107-113.

 

5 Matthews, T. G., Thompson, C. V., Wilson, D. L., Hawthorne, A. R. & Mage, D. T., Air velocities inside domestic environments: an important parameter in the study of indoor air quality and climate, Environment International, 1989; 15: 545-550.

 

6 Yu, I. T. et al. Evidence of airborne transmission of the severe acute respiratory syndrome virus. New England Journal of Medicine, 2004; 350, 1731-1739.

 

7 Miller, S. et al., Transmission of SARS-CoV-2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event. medRxiv, 2020; doi: https://doi.org/10.1101/2020.06.15.20132027 (accessed 23/06/2020).

 

8 Buonanno et al., Quantitative assessment of the risk of airborne transmission of SARS-CoV-2 infection: perspective and retrospective applications. medRxiv, 2020; doi: https://doi.org/10.1101/2020.06.01.20118984 (accessed 23/06/2020).

 

Downloaded from https://academic.oup.com/cid/article abstract/doi/10.1093/cid/ciaa939/5867798 by guest on 06 July 2020 Accepted Manuscript

 

9 Cai, J., Sun, W., Huang, J., Gamber, M., Wu, J. and He, G., 2020. Indirect virus transmission in cluster of COVID-19 cases, Wenzhou, China, 2020.

 

10 Li, Y. et al. Evidence for probable aerosol transmission of SARS-CoV-2 in a poorly ventilated restaurant. medRxiv, 2020; doi: https://www.medrxiv.org/content/10.1101/2020.04.16.20067728v1 (accessed 05/06/2020).

 

11 Kulkarni, H. et al. Evidence of respiratory syncytial virus spread by aerosol. Time to revisit infection control strategies? American Journal of Respiratory and Critical Care Medicine, 2016; 194: 306-316.

 

12 Kim, S.H. et al. Extensive viable Middle East Respiratory Syndrome (MERS) coronavirus contamination in air and surrounding environment in MERS isolation wards. Clinical Infectious Diseases, 2016; 63: 363–369.

 

13 van Doremalen, N. et al. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. New England Journal of Medicine, 2020; 382: 1564-1567.

 

14 Liu, Y. et al. Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals. Nature, 2020; in press.

 

15 Lin, K. & Marr, L. C. Humidity-dependent decay of viruses, but not bacteria, in aerosols and droplets follows disinfection kinetics. Environmental Science & Technology, 2020; 54(2): 1024-1032.

 

16 World Health Organization. Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations: scientific brief, 27 March 2020; (No. WHO/2019nCoV/Sci_Brief/Transmission_modes/2020.1) (accessed 05/06/2020).

 

17     Somsen, G.A., van Rijn, C., Kooij, S., Bem, R.A. and Bonn, D. Small droplet aerosols in poorly ventilated spaces and SARS-CoV-2 transmission. The Lancet. Respiratory Medicine, 27 May 2020; in press.

 

Downloaded from:

 

https://academic.oup.com/cid/article-abstract/doi/10.1093/cid/ciaa939/5867798 by guest on 06 July 2020  

 

Fuente: file:///C:/Users/Marco/Desktop/x.pdf

 

Fuente: https://www.voltairenet.org/article210486.html

 

*Marcos Jesús Concepción Albala… (Trinidad/Casilda, S.S., Cuba) Agosto 03 1947… Reside en Miami, Florida, Estados Unidos… Licenciado en Gestión Comercial Internacional… @: marcosjesus360@yahoo.com... Director de la Agencia de Información ‘ArgosIs-Internacional’ en la Red…  Web: http://www.argosisinternacional.com...  @: argosisdirector@yahoo.com - twitter.com/ArgosIs - twitter.com/ArgosIsUSA - twitter.com/ArgosIsMiami - twitter.com/ArgosIsCuba

 

“La sociedad no puede ser enemiga de sí misma... Si un medio de comunicación no está aportando y contribuyendo a la elevación educativa, cultural y espiritual de todos sus miembros merece ser cerrada, así de simple... Debido a que la propiedad de los medios de comunicación no es la libertad de expresión de la sociedad”... ‘ArgosIs-Internacional’ es una Agencia de Información en la Red, de carácter social (POR AHORA) con sede en la Ciudad de Miami, Florida, Estados Unidos; fundada en 1991… Web: http://www.argosisinternacional.com… Miembro de la ‘Federación Latinoamericana de Periodistas’ (FELAP)… Web:  http://www.felap.info...

 

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‘ArgosIs-Internacional’ es una Agencia de Información en la Red, de carácter social (POR AHORA) con sede en la Ciudad de Miami, Florida, Estados Unidos; fundada en 1991… Web: http://www.argosisinternacional.com… Miembro de la ‘Federación Latinoamericana de Periodistas’ (FELAP)… Web:  http://www.felap.info...

 

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