Biologic barriers are present from conception. Surrounded by the amniotic membrane, we are protected from most pathogens. Upon its rupture and our ride down the birth canal we start the self versus society struggle.  Hepatitis B, polio, rotavirus, diphtheria, tetanus and pneumococcal vaccinations are our initial immune barrier. Child proofing mechanical barriers (plug locks, stair locks, edge protectors) are present during our formative years. Car seats and later seat belts protect us from motor vehicle morbidity. Science has driven these medical protections and public health measures have orchestrated their distribution to the public and their acceptances as standards of care.

Societal barriers have protected humans for eons from human aggression, accidents and microbes. The Caves of Lascaux  protected Paleolithic man, The Great Wall of China retarded invasion by the Mongols. The Roman emperor Hadrian built his namesake “wall” in Northern England to keep out the “barbarians.” Ramparts and moats around European castles in the Middle Ages slowed the devastation wrought by the Vikings. In our lifetime we put up with anti-terrorist barriers at TSA checkpoints at all U.S. airports. Physical barriers and screening techniques have been shown over time to decrease disease and death from outside threats to our well-being.

Our protection from COVID-19 now demands a barrier to our nasopharynx. We are now safely surrounded by our homes’ four walls and limited “world” contact through our UPS and Amazon delivery services. In order to integrate into society we need extra protection from the virus. A mask or “facial condom” could provide us with the protection and turn human interaction into an acceptable risk. We are now familiar with the N95, surgical, and home-made masks. We have YouTube videos of media celebrities constructing masks. Now,  “mask science” is the next logical step to assure that our efforts are working to prevent Covid-19 transmission. What we really need is some evidence based guidelines developed from a controlled study.

 The geometry is well known: N95 keeps out 95% of particles that are as small as 0.3 microns; droplets containing COVID-19 are 50 microns or less. Droplet spread is 6 feet, more if sneezing or aerosol transmission is involved from the contact. What we don’t know is what materials and layering are most effective against virus spread when used in a real world scenario.

Compliance and comfort are inextricably linked. When I donned a mask in the OR, my face felt like I was in the microclimate of Miami during the summer and my eyeglasses fogged up like winter in London. We have designers and aerosol engineers that can overcome “wearability” issues that could lead to improved compliance. We have industry and universities that have the capability of testing combinations of fabric under simulated and actual environmental conditions.  Distribution capabilities are available to send masks to every household in the United States utilizing the Postal Service.

Americans have internalized the use of seatbelts and TSA screenings in my lifetime. Introducing and complying with  a “new fence” is easier when the alternative may be a painful respiratory death. Wearing a fashionable, comfortable and effective face mask should become the “new normal.”  The design, efficacy and distribution is simply just one more barrier for science to overcome.