COVID-19: Aerosolization spread possible, not just droplets: Wear a Mask
John Campbell, RN PhD, in his April. 4, 2020 update notes that the coronavirus can be spread through aerosolized transmission (3m44s), meaning amounts which can be suspended in air for hours, and not just droplets, which rapidly fall to the ground, according to Dr. Anthony Fauci of the US White House Coronavirus Task Force. This revises previous understanding and is why universal wearing of even homemade masks is recommended when out in public.
Looking for a specific recommendation, the closest I find is this statement of Fauci's:
"Because of that and because of some recent information that the virus can actually be spread even when people just speak, as opposed to coughing and sneezing, the better part of valor is that when you’re out, and you can’t maintain that six-foot distance, to wear some sort of facial covering.
In "Face Coverings Help as Virus Can Spread by Talking, Fauci Says" (Bloomberg) April 3, 2020.
That piece continues:
Fauci stressed that the most important recommendation is still to keep six feet away from people, regardless of whether you’re wearing a face covering. And he said the face covering recommendation “should in no way ever take away from the availability of masks that are needed for the health-care providers.” The face covering recommendation is on top of the call to stay six feet away from people, “not as a substitute for it,” he said.
Via Wikipedia's Coronavirus Disease 2019 article, a reference to the National Academies of Science, Engineering, and Medicine article "Rapid Expert Consultation on the Possibility of Bioaerosol Spread of SARS-CoV-2 for the COVID-19 Pandemic (April 1, 2020)". This is a letter -- that is, a credible account though. not formally reviewed research -- summarizing experience is several medical facilities directly treating confirmed, and often intubated COVID-19 patients. That is, close to a worst-case scenario:
A study of SARS-CoV-2 raises concerns about transmission via aerosols generated from droplet contaminated surfaces. Liu, et. al. collected 35 aerosol samples in two hospitals and public areas in Wuhan. From samples collected in patient care areas the highest concentration of virus was found in toilet facilities (19 copies m^3^), and in medical staff areas the highest concentrations were identified in personal protective equipment (PPE) removal rooms (18-42 copies m^3^). By comparison, in all but two crowded sites, the concentrations of virus found in public areas was below 3 copies m^3^. The authors conclude that a direct source of SARS-CoV-2 may be a virus-laden aerosol resuspended by the doffing of PPE, the cleaning of floors, or the movement of staff. It may be difficult to re-suspend particles of a respirable size. However, fomites could be transmitted to hands, mouth, nose or eyes without requiring direct respiration into the lungs.
(The paper is freely downloadable though an email address is requested but not verified. Any email-shaped string will suffice.)
Particle densities on tested surfaces in these facilities are relatively low -- if you're exposed. by this route, the inoculum, the amount of infectuous material received, is small. This is probably a low-risk exposure, especially for incidental contact. But the risk is measureable and non-zero. For those in constant or repeated exposure to such environments, e.g., public-facing positions, the risk is far greater than for those with occasional -- once a week or two, say -- exposures.
Upshots:
- This represents a change in prior medical understanding. And the advice I've previously relayed.
- Masks here are principally aimed at reducing transmission by the wearer, not to the wearer. You're protecting others far more tha yourself.
- Virus-grade masks -- N95 or equivalent -- should still be reserved for medical personnel, first responders, critical services workers, including grocery and other essential retail workers, and the confirmed or suspected ill with COVID-19.
- DIY and non-virus-grade masks offer limited to no protection against receiving the virus, and are NOT a substitute for other nonpharmaceutical interventions: staying at home, washing your hands, not touching your face, keeping a healthy distance of at least 6 feet / 2 meters preferably more. A false sense of security is a real risk itself.
- A used mask is an infected mask and must be sterilised before it can be safely handled. Boiling, heat, bleach, Lysol, hydrogen peroxide, UV light, or 60%+ alcohol, and possibly soap or detergent, are recommended treatments. Longer treatment is better, generally 5-10 minutes, even longer for UV. Certain mask materials can be damaged themselves by various decontamination processes.
Clarifying a point: there's never been a question to my mind that masks are effective at reducing disease transmission, the question has been whether universal wearing has been recommended, for the general population, given intrinsic shortages of supply. The question has always been who to deploy masks to for greatest common population benefit. And the answer, for now, is "even less-effective masks, to more people, is better".
https://youtube.com/watch?v=LsxVRnNGl5A&t=3m44s
#covid19 #coronavirus #faceMasks #DrFauci #AnthonyFauci #aerosols #StayTheFuckHome #WashYourHands #DontTouchYourFace
