we need to be discussing #masks.
It seems that we keep avoiding the best COVID control solution, public wearing of masks.
Lockdowns and social distancing are the lowest level of control on the hierarchy of control. Lockdown is entirely dependent on behavioural compliance. The most optimistic of us could only expect 80% compliance. Many people will not comply for a variety of reasons that range from indifference through to ignorance or lack of understanding. Even in lock down conditions, the evidence for behaviour breaches is prevalent at our shops, public places and workplaces.
Where people interact in the same space, there are effectively three inter-dependent strategies to prevent cross-infection; separation, hand hygiene and masks. However, a mask is not always a mask in the #COVID context. Harvard business has published an excellent article (We Need Better Masks).
We do know that to protect against virus aerosol inhalation, the reliable mask choice is a positive pressure respirator. All other masks have limited protective benefit depending on design, materials and use. However, the emerging evidence is clear in that by reducing virus exhalation there is a clear benefit from mask-wearing, even with inferior mask designs and materials.
If we are all in this together, then we can all do two things: wear a mask in public and at work and have the #COVIDApp installed on our phones. This is how we will avoid imposing lockdown and its unwanted outcomes over the coming months.
In promoting masks in the public domain, it is important that good guidance is widely promoted. A mask in the COVID context has two purposes, (1) prevent inhalation and (2) prevent exhalation. To prevent exhalation, the mask should not have an exhalation valve, as this allows aerosols to pass unfiltered from the mask with increased velocity. Many varieties of the disposable masks are fitted with this feature and therefore unsuitable for COVID use. This is a point that is not receiving sufficient attention.
There is increasing evidence that exhalation filtering is the primary benefit of public mask use. We need clear guidance and communication for the public use of masks. The CDC now recommends that people wear cloth face coverings in public settings and when around people who don’t live in your household, especially when other social distancing measures are difficult to maintain. The CDC states that cloth face coverings may help prevent people who have COVID-19 from spreading the virus to others. The CDC advises that cloth face coverings are most likely to reduce the spread of COVID-19 when they are widely used by people in public settings.
The public solution needs to be innovative, and not constrained to industrial capability. We need to enable the public to produce their own solutions. A recent study showed that filtration just shy of N95 could be achieved with combinations of cotton and other common fabrics like silk, flannel, and chiffon. Other research has demonstrated how the fit can be enhanced by lining the outside of masks with material from a nylon stocking or creating a brace using rubber bands. Researchers are experimenting with fabrics that deploy low-level electric charges and can be inserted into masks to neutralize viral particles.
The Fix the Mask initiative of former Apple engineer Sabrina Paseman (co founder) is an organisation that offers designs for a brace to make surgical masks more effective as hospitals grapple with N95 mask shortages. One version of the brace can be made at home by linking three rubber bands together, while another can be made from a rubber sheet. Fix The Mask has already made two iterations of its brace, and it’s working on a third that’s more comfortable and durable, and is seeking OSHA accreditation.
This is call to action for the safety and public health communities to advocate for mask use. Unless we take this initiative whilst the virus is active in our communities, we will continue to impose lockdowns and its hardships for those affected.
References:
COVID Personal Protective Equipment: Questions and Answers - CDC
Respiratory Virus Shedding in Exhaled Breath and Efficacy of Face Masks: Nat Med . 2020 May;26(5):676-680. doi: 10.1038/s41591-020-0843-2. Epub 2020 Apr 3.
Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks : ACS Nano 2020, 14, 6339−6347
