A Comprehensive and Layered Approach to Stopping the Spread of COVID-19


Stopping the Spread of Covid-19

If most people are wearing their masks, why is COVID-19 is still spreading? A team of PNWU scientists offers expert insight into a comprehensive and layered approach to stopping the spread of the SARS CoV-2 virus.

If most people are wearing their masks, why is COVID-19 still spreading? A team of PNWU scientists offer expert insight into a comprehensive and layered approach to stopping the spread of the SARS CoV-2 virus.

The Facts:

Wearing a mask CORRECTLY to control the spread of this virus is important, but it is but one tool in our toolbox.

In addition to masks, we should all:

  • Stay close to home
  • Stay at least six feet from others
  • Frequently wash or sanitize our hands
  • NOT socialize in groups with people outside our own household


Everyone is susceptible to the virus, and a comprehensive and layered approach is the best way to protect against it.

A Layered Approach:

When, as a child, we learned how to safely cross a street, we used a step-by-step layered process.

We learned where crosswalks were, how to push the button to activate the crosswalk’s mechanical lights, to wait for the “WALK” sign to light up, to adhere to the time limits for crossing, to stay within the lines marking the crosswalk, and to look both ways while stepping off and crossing the street. While most adults in our American society do not actively think about how many individual steps it takes to cross a street safely, a person new to completing this task would more likely go through a mental checklist to accomplish all of those steps. The same multi-step process holds for combating the spread of COVID.

Putting on a mask to control the spread of a respiratory disease is much like putting on one piece of cold-weather clothing to stay warm. That one piece will help, but not nearly as well as multiple layers. Masks should be combined with other recommended non-pharmacological interventions, just as scarves should be combined with gloves, hats, coats, thick socks, etc.

You should wear a mask, but you should also do your best to stay close to home, keep six feet of distance from others, frequently wash or sanitize your hands, and avoid socializing with people outside of your household.

Additionally, masks should be worn over BOTH the nose and mouth, as viruses come from the nose as well. Only wearing a mask over your mouth is like only draping an unzipped coat over your shoulders.

The Science:

Since February, we have learned a great deal about the virus and its consequences. We now need to apply what we know to mitigate its transmission, both before and after infection occurs.

A very important scientific study was published in June 2020 reporting very good efficacy of individual “non-pharmaceutical public health interventions” (“NPIs”) in controlling coronavirus transmission across the three emerging diseases caused by related viruses in the last 18 years: SARS, MERS, and COVID-19. This publication determined that facemask use decreased viral transmission by a highly statistically significant 85%; physical distancing providing a further 82% reduction in viral transmission, and eyewear contributed another 78% reduction in transmission. The cumulative effect of layering NPIs is even more effective.

We have already witnessed similar results in the decrease in COVID transmission in our own Yakima county. The most direct Yakima-based data correlating mask use and COVID-19 incidence come from “before” and “after” June 22, 2020 -- the date when the “Mask Up to Open Up” campaign started.

The Yakima Health District sent observers to perform “convenience sampling” of people entering large retail emporia who were wearing masks. When only 20% of the patrons were wearing masks, during the two-week period before June 22, 2020, Yakima County had a COVID-19 incidence rate of ~850 cases/100,000. By August 3, 2020, 90% of patrons in the surveys were wearing masks, and the two-week incidence rate was ~300 cases/100,000 population. These data were not confused by outbreaks linked to holiday gatherings, which has more recently been the case.

Controlling Transmission to Prevent an Infection: The multi-step approach recommended above: wear a mask correctly, stay at home, keep six feet from everyone, not in your household, sanitize hands frequently.

Controlling Transmission After an Infection Has Occurred: The traditional public health triad of “test, trace, and isolate” works only if each of the steps is followed. We cannot trace if we do not or cannot test. Tracing contacts and informing them of their exposure allows them to isolate and protect others.

In a Nutshell:

If we all practice the recommended layered approach, there will be fewer COVID cases in our community.

Vigilance, using comprehensive approaches, continuing to grow in our knowledge, applying what we have learned with an approach of solidarity, not becoming fatigued in processing our newly required risk analysis in everyday life, and evaluating how to improve our responses with the knowledge that comes to us as lifelong learners will lead us through this if we can be united.


Written by Kimberly Taylor, Ph.D., William Elliott, M.D., Ph.D., Albert Brady, M.D., and Julie Randolph-Habecker, Ph.D.