Face Masks Against COVID-19: An Evidence Review

Howard, J.; Huang, A.; Li, Z.; Tufekci, Z.; Zdimal, V.; van der Westhuizen, H.; von Delft, A.; Price, A.; Fridman, L.; Tang, L.; Tang, V.; Watson, G.L.; Bax, C.E.; Shaikh, R.; Questier, F.; Hernandez, D.; Chu, L.F.; Ramirez, C.M.; Rimoin, A.W. Face Masks Against COVID-19: An Evidence Review. Preprints2020, 2020040203 (doi: 10.20944/preprints202004.0203.v1). 

La ciencia sobre el uso de máscaras por parte del público en general para impedir la transmisión de COVID-19 avanza rápidamente. Los formuladores de políticas necesitan orientación sobre cómo la población en general debe usar máscaras para combatir la pandemia de COVID-19. Aquí, sintetizamos la literatura relevante para informar múltiples áreas: 1) características de transmisión de COVID-19, 2) características de filtrado y eficacia de las máscaras, 3) impactos estimados en la población del uso generalizado de máscaras comunitarias, y 4) consideraciones sociológicas para las políticas relacionadas con las máscaras .

Una vía primaria de transmisión de COVID-19 es a través de pequeñas gotas, y se sabe que es transmisible desde individuos presintomáticos y asintomáticos. La reducción de la propagación de la enfermedad requiere dos cosas: primero, limitar los contactos de las personas infectadas a través del distanciamiento físico y el rastreo de contactos con la cuarentena adecuada, y segundo, reducir la probabilidad de transmisión por contacto usando máscaras en público, entre otras medidas. La preponderancia de la evidencia indica que el uso de mascarillas reduce la transmisibilidad por contacto al reducir la transmisión de gotitas infectadas en contextos tanto de laboratorio como clínicos. El uso de máscaras públicas es más efectivo para detener la propagación del virus cuando el cumplimiento es alto. La disminución de la transmisibilidad podría reducir sustancialmente el número de muertos y el impacto económico, mientras que el costo de la intervención es bajo. Por lo tanto, recomendamos la adopción del uso de máscaras de tela públicas, como una forma efectiva de control de la fuente, junto con las estrategias existentes de higiene, distanciamiento y localización de contactos. Recomendamos que los funcionarios públicos y los gobiernos alienten firmemente el uso de máscaras faciales generalizadas en público, incluido el uso de una regulación adecuada.

Would everyone wearing face masks help us slow the pandemic?

By Kelly ServickMar. 28, 2020 , 8:00 AM

As cases of coronavirus disease 2019 (COVID-19) ballooned last month, people in Europe and North America scrambled to get their hands on surgical masks to protect themselves. Health officials jumped in to discourage them, worried about the limited supply of masks for health care personnel. “Seriously people-STOP BUYING MASKS!” began a 29 February tweet from U.S. Surgeon General Jerome Adams. The World Health Organization and U.S. Centers for Disease Control and Prevention (CDC) have both said that only people with COVID-19 symptoms and those caring for them should wear masks.


Sui Huang Mar 26 · 12 min read

The official recommendation in the United States (and other Western countries) that the public should not wear face masks was motivated by the need to save respirator masks for health care workers. There is no scientific support for the statement that masks worn by non-professionals are “not effective”. In contrary, in view of the stated goal to “flatten the curve”, any additional, however partial reduction of transmission would be welcome — even that afforded by the simple surgical masks or home-made (DIY) masks (which would not exacerbate the supply problem). The latest biological findings on SARS-Cov-2 viral entry into human tissue and sneeze/cough-droplet ballistics suggest that the major transmission mechanism is not via the fine aerosols but large droplets, and thus, warrant the wearing of surgical masks by everyone.

Not wearing masks to protect against coronavirus is a ‘big mistake,’ top Chinese scientist says

By Jon Cohen Mar. 27, 2020 , 6:15 PM

Chinese scientists at the front of that country’s outbreak of coronavirus disease 2019 (COVID-19) have not been particularly accessible to foreign media. Many have been overwhelmed trying to understand their epidemic and combat it, and responding to media requests, especially from journalists outside of China, has not been a top priority.

Science has tried to interview George Gao, director-general of the Chinese Center for Disease Control and Prevention (CDC), for 2 months. Last week he responded.

The untold origin story of the N95 mask


It’s hard to think of a symbol of COVID-19 more fraught than the N95 respirator. The mask fits tightly around the face and is capable of filtering 95% of airborne particles, such as viruses, from the air, which other protective equipment (such as surgical masks) can’t do. It’s a life-saving device that is now in dangerously short supply. As such, it has come to represent the extreme challenges of the global response to COVID-19.

Asymptomatic Carriers Are Fueling the COVID-19 Pandemic. Here’s Why You Don’t Have to Feel Sick to Spread the Disease

Experts talk about what it means to be infected without being sick, and how that seems to be making the novel coronavirus very easy to spread. 

By Jillian Mock March 26, 2020 3:36 PM

This week, the White House issued a warning for anyone who recently fled New York City: Quarantine yourself for a full 14 days or risk spreading COVID-19 to a new community — regardless of whether you’re showing symptoms.

Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1


A novel human coronavirus that is now named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (formerly called HCoV-19) emerged in Wuhan, China, in late 2019 and is now causing a pandemic.1 We analyzed the aerosol and surface stability of SARS-CoV-2 and compared it with SARS-CoV-1, the most closely related human coronavirus.2