By JOHN RICHARD SCHROCK
In May, ninety-nine percent of U.S. COVID-19 hospitalizations and deaths occurred in unvaccinated people, according to the CDC Director and reported by the Associated Press. That means that “breakthrough” cases of folks getting this coronavirus remain exceedingly low and that very few end up in the hospital. The running average of daily deaths from this virus is now under 300, but cases are again rising in regions with low vaccination rates.
The most recent research into the level of protection from face masks appears in the June 25 issue of the journal Science: “Face masks effectively limit the probability of SARS-CoV-2 transmission.” The multinational research team used measures of the quantities of airborne virus to determine the safety and effectiveness of masks. They found that a person typically emits 3,000,000 particles during a 30-minute period; thus “...we cannot avoid inhaling particles generated by another person.” And respiratory diseases usually require from “...a few tens to thousands of viruses” to establish disease.
The average time of being infectious for COVID-19 is ten days and the average number of human contacts range from 10 to 25 per day. But the risk of transmission through a surgical mask becomes very high in virus-rich conditions, such as a hospital room full of COVID-19 patients, and then masks will not prevent transmission. Self-contained hazmat suits and other equipment is then necessary.
The researchers broke down their analysis into three scenarios. “Source control” is where the infected person wears a mask and the aerosol particles are breathed out through nose and mouth through some variety of mask. “Wearer protection” is where an uninfected person is wearing a mask to filter the aerosol particles being breathed in from the immediate surroundings. “Universal masking” is where both are wearing a mask. The researchers do distinguish between surgical and N95 masks and their data show the differences in filter efficiency in cases of sneezing, coughing, speaking and breathing.
Aerosols are airborne particles smaller than 100 ÎĽm, and those smaller than 5 ÎĽm remain suspended in the air for much longer times, thereby causing higher virus concentrations over time. One very important factor in the charts is that the properly worn face mask of an infected person is significantly more important in reducing transmission than a mask prevents an uninfected person from becoming infected. Of course, the lowest rate of transmission is when both are wearing face masks.
This is solid evidence that I-wear-my-mask-to-protect-you and you-wear-your-mask-to-protect-me. In other words, masks are more effective at decreasing dispersal of virus-bearing aerosols when worn at the source. When virus-bearing aerosols spread out in the air, they arrive in lower concentrations when they reach the uninfected person breathing them in through a mask.
The idea that we wear masks to protect others is the collectivist mindset of people in South Korea, Taiwan, mainland China, Japan, Hong Kong, etc. The mistaken idea that we only wear masks to protect ourselves is the individualistic mindset of Western countries and especially Americans.
That has led to certain Senators mistakenly proclaiming that after one has received the full vaccinations against COVID-19 and enough time as passed to make it fully effective, then being able to throw away that mask is your rightful reward. But none of the vaccines are 100 percent effective in preventing “breakthrough” infections. And we still know that 30 percent or more of infected persons may never show symptoms. Thus there remains the possibility that the immunized person may still serve as a silent (asymptomatic) carrier who can infect others.
Last Wednesday, the director of the Centers for Disease Control and Prevention reiterated that fully vaccinated people did not need to wear masks in most situations. But many virologists and epidemiologists consider this premature. The World Health Organization stands by its guidance that everyone, whether vaccinated or not, should continue to wear masks due to a global surge in the highly contagious Delta variant.
Meanwhile, large numbers of Americans are shedding masks in the belief that the pandemic is mostly over. It isn’t.
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John Richard Schrock has trained biology teachers for more than 30 years in Kansas. He also has lectured at 27 universities in 20 trips to China. He holds the distinction of “Faculty Emeritus” at Emporia State University.