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Mandates for mask use in public during the recent COVID-19 pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing such masks reduces the likelihood for an infected person to spread the disease, but many of these mask designs have not been tested in practice. We have demonstrated a simple optical measurement method to evaluate the efficacy of masks to reduce the transmission of respiratory droplets during regular speech. In proof-of-principle studies, we compared a variety of commonly available mask types and observed that some mask types approach the performance of standard surgical masks, while some mask alternatives, such as neck fleece or bandanas, offer very little protection. Our measurement setup is inexpensive and can be built and operated by non-experts, allowing for rapid evaluation of mask performance during speech, sneezing, or coughing.

In fact masks (and faceshields) supplemented with constraints of superspreader events can save us trillions of dollars in future lockdowns (and lawsuits) and be potentially sufficient (under adequate compliance) to stem the pandemic. Bureaucrats do not like simple solutions.

Our crisis of inertia as revealed by our continuing reliance on cloth masks

So many of us, including me, have been focused on the failure of the federal response to Covid-19, watching President Trump's catastrophe-by-public-policy roll out day after day since late February. I've written a lot about it in these pages. In a misplaced triumphalism, some people in states that have managed to have a relatively quiet summer with low rates of Covid-19 cases have chastised those in states with renewed outbreaks as being foolish or unheeding of scientific advice, as governors still slow-walk the response to the disease and ordinary people shun masks and flock to social gatherings. We all like to think of ourselves as different, doing the right thing, doing our part.

Aerosol transmission of viruses must be acknowledged as a key factor leading to the spread of infectious respiratory diseases. Evidence suggests that SARS-CoV-2 is silently spreading in aerosols exhaled by highly contagious infected individuals with no symptoms. Owing to their smaller size, aerosols may lead to higher severity of COVID-19 because virus-containing aerosols penetrate more deeply into the lungs (10). It is essential that control measures be introduced to reduce aerosol transmission. A multidisciplinary approach is needed to address a wide range of factors that lead to the production and airborne transmission of respiratory viruses, including the minimum virus titer required to cause COVID-19; viral load emitted as a function of droplet size before, during, and after infection; viability of the virus indoors and outdoors; mechanisms of transmission; airborne concentrations; and spatial patterns. More studies of the filtering efficiency of different types of masks are also needed. COVID-19 has inspired research that is already leading to a better understanding of the importance of airborne transmission of respiratory disease.

The phenomenon where a mutation overrides another genetic defect is known as genetic suppression and it is not unique to yeasts. Genome sequencing studies have revealed individuals who remain healthy despite carrying catastrophic inborn errors whose usual harmful effects are somehow masked by other unknown changes in their genomes.