COVID19, infection and masks

According to the most recent report by the WHO (April 6) 1, the two main routes of transmission of the COVID-19 virus are respiratory droplets and contact. Any person who is who has respiratory symptoms, or is in the incubation period, carries the risk of exposing close contacts to potentially infective droplets.

Although the systematic use of masks is not supported as as the sole effective measure to prevent contagion, many countries are considering or have already decided to enforce the use of masks in public spaces 2,3,4,5,6

The masks that are recommended for the general public are the so-called surgical masks. They do not protect the wearer from catching the virus, but they form a physical barrier that prevents infectious droplets from reaching the person in front 7,8.

Many mask designs have been proposed since the onset of the crisis, from the easiest to the most creative ones. Various materials have also been used, with various effectiveness 9. Some facilities have used derivatives of PET to create clear screens for medical personnel 12,13.

Given that most droplets are expelled through the mouth, and that the main purpose of surgical masks is to ensure outward protection, it may make sense to develop a device that covers that and deviates them from landing on another person’s face.

Surgical masks: great as a start, but not perfect for everyday use

Big issues related to current surgical masks are the following:

  1. Disinfection: masks have to be cleaned every few hours to avoid the formation of other bacterial or viral colonies. Disinfection at home with UV-based devices (sun included) is either time-consuming or requires special equipment Correct use: many people use the mask incorrectly or put it on and off several times, thus actually increasing the risk of infection.
  2. Reuse: disposable masks must be continuously produced, additionally disposable masks contribute to environmental pollution and waste production. Washable masks made of cloth are great, but they do not dry quickly and they need more time for mass production. Also they also cannot be worn for long hours for the same problem as (1), and they can carry the same infection risks as in (2).
  3. Social factor: surgical masks cover the mouth, which is a crucial factor in facial expressions and can impact commercial as well as interpersonal relationships 10,11. Communication is greatly impaired and may be difficult for people with disabilities (e.g. deaf) or speaking a different language.
  4. Comfort during daily life and work: when doing high-intensity activities (e.g. running, lifting heavy weights, doing physical work etc), surgical masks prevent correct perspiration and increase the wearer’s discomfort. They make glasses fog during winter.

Can we fix that?

The mask alternative I have thought about is easy to generate even by a private citizen, impacting as little as possible on life activities, transparent, reusable and disinfectable within minutes.

It is composed of several parts. A 3D printed skeleton (CAD files openly available) is worn like a headband. To this, one can clip a transparent plastic screen. The screen is at an angle with respect to the vertical direction, so that it is able to deviate most droplets towards the floor before they reach the face of the individual in front. The screen could be also developed industrially, but for general usage I would imagine that any clear plastic cut, for example from PET bottles or A4 thick transparent plastic sheet commonly found in stationary shops, could work.

The 3D printing could be made based on actual user pictures or head measurements, to make it sit comfortably on the user’s head for many hours.

The screen can slide to the front or move back towards the ear by the simple push of a lever.

An intense #EUvsVirus weekend

I started from scratch on Friday, I just had in mind that I wanted to create a solution to all the issues above and I wanted take this opportunity to brainstorm with so many people with very diverse backgrounds to find a solution. I did so and came up with multiple possible designs, but progressively refined the idea towards maximum reproducibility by simple individuals. I also searched for evidence supporting most of my claims, put together this justifying document and developed a rough business canvas, although this is meant to be a free-for-use solution to tackle an immediate issue. I reached out to multiple registered participants to see if they would like to join the challenge. Although unsuccessful, I have briefly spoken with a participant that knows a bit about 3D printing and indicated that the design should be feasible, although slow to produce. Also, the feedback from a behavioural product designer indicated that the first iteration of the product makes sense and it is great to keep daily activities in mind (e.g. eating). A further refinement would be to pay close attention to the design and feel of the 3D printed skeleton, and that the screen doesn't prevent people from breathing properly. A graphics designer created a nicer drawing of the mask and a rendering on a real person's face.

It was worth it...

This solution could bring several immediate advantages:

  1. Resolve the issue of disinfection of surgical masks used by the general public: the clear plastic sheet can be easily removed and disinfected with store-bought disinfectant every couple of hours, and then put on again right after
  2. Allow people to still work, eat, do activities and interact with people by seeing their full face, thanks to the clear shield
  3. Less chances of contagion by manipulating the mask the wrong way, for multiple wears and removals throughout the day, thanks to the lever and the rail system
  4. Resolve the issue of continuous and possibly prolonged mask supply/purchase: there is only one mask per person needed, that can be reused as many times as needed

...also for the longer term

I hope this will have to be used only for a short/medium period. It would anyway keep on having the same advantages on the long term, plus it would make people discover the value of 3D printing facilities in their neighbourhoods and stimulate the development of these very helpful service providers - that are also a channel to quickly introduce novel prototypes into a society. Also, this process would support local economy.

It just needs a bit more work:

  1. Shortly verify that the shielding provides a protection similar to surgical masks, in terms of droplet landing on the other person’s face. Perfection sizing and angle and subsequent design, based on results.
  2. Find a skilled CAD designer and 3D printer, who would support the prototyping and further refinements for the skeleton
  3. Find a clear sheet producer (better if from recycled yet shielding materials), to provide an alternative, for purchase to people that to not want to use plastic bottle/clear sheet cuts or reusable materials
  4. Distribute the CAD drawings to the general public for individual use


  2. (Belgium)
  3. (France)
  4. (Italy)
  5. (Germany)
  6. (Spain)
  10. smiling helps in unfamiliar relationships
  11. smiling influences consumer behaviours

Video created with -Some of the images used in the video may be copyrighted (Google Images) Thanks to Benjamin Bertram for the mask rendering.

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