By Shereen Siewert
Mask use has been the topic of hot debate throughout Wisconsin, as surrounding states and an increasing number of municipalities have recently passed mask ordinances and mandates.
Illinois, Michigan and Minnesota all have mandatory mask requirements in place. Late last week, Gov. Tony Evers told reporters a statewide mask mandate for Wisconsin remains a possibility, despite the threat of a legal challenge from Republicans.
“Clearly, the number of consecutive record increases in cases have accelerated our consideration,” he said.
Mask advocates and some researchers say there are two main reasons to wear masks. There’s some evidence of protection for the wearer, but the stronger evidence cited is that masks protect others from catching an infection from the person wearing the mask. Infected people can spread the virus just by talking and many people with COVID-19 are unaware they are carrying the virus.
Aa growing number of scientific studies support the theory that masks can help minimize the spread of COVID-19. Still, Americans as a whole are divided on the issue, as are some researchers and members of the medical community.
In a July 14 editorial published in the Journal of the American Medical Association (JAMA), the Centers of Disease Control and Prevention reviewed the most recent science and reaffirmed the organization’s stance that cloth face coverings are a critical tool in the fight against COVID-19 that could reduce the spread of the disease, particularly when used universally within communities.
“There is increasing evidence that cloth face coverings help prevent people who have COVID-19 from spreading the virus to others,” the CDC stated in a press release.
“We are not defenseless against COVID-19,” said CDC Director Dr. Robert R. Redfield. “Cloth face coverings are one of the most powerful weapons we have to slow and stop the spread of the virus – particularly when used universally within a community setting. All Americans have a responsibility to protect themselves, their families, and their communities.”
But not everyone is on board, even in the medical community, said Dr. Calvin Sprik, of Wausau.
“We may find out in the future that it helps, but now we do not know and its doubtful,” Sprik said. “In light of the ‘magic’ effect of wearing a mask seems to have per the politicians and policy makers, it is important to base it on science.”
What the research says
Sprik pointed to several studies, along with a University of Minnesota commentary that criticized the data being used to support masks for all. The commentary, published by Lisa M Brosseau, ScD, and Margaret Sietsema, PhD, said there is “no scientific evidence” cloth masks are effective in reducing virus transmission and their use could result in those wearing masks to relax other distancing efforts.
Later, facing a rash of criticism, the university on July 16 added a clarification to the commentary that stated:
“We agree that the data supporting the effectiveness of a cloth mask or face covering are very limited. We do, however, have data from laboratory studies that indicate cloth masks or face coverings offer very low filter collection efficiency for the smaller inhalable particles we believe are largely responsible for transmission, particularly from pre- or asymptomatic individuals who are not coughing or sneezing. At the time we wrote this article, we were unable to locate any well-performed studies of cloth mask leakage when worn on the face—either inward or outward leakage. As far as we know, these data are still lacking.”
The evidence that does exist comes both from laboratory studies and real-world scenarios.
For example, one recent laboratory experiment used laser lights to visualize respiratory droplets expelled by test subjects who repeated the phrase “stay healthy.” Each time the subjects spoke, their speech generated hundreds of droplets ranging in size from 20 to 500 micrometers. The research concluded that covering the speaker’s mouth with a damp washcloth blocked nearly all of them.
Some of the more compelling research includes a recent study that used publicly available data to calculate the COVID-19 growth rate before and after mask mandates in 15 states and the District of Columbia between the end of March and late May of 2020. Researchers found a significant slowdown in the daily growth rate in those areas and concluded that mask mandates may have prevented up to 450,000 new virus cases.
Critics point to a 2015 study that concluded cloth masks were ineffective in high risk situations. In the study, researchers found that moisture retention, reuse, and poor filtration could increase wearers’ risk of infection.
But Kim Schive at MIT Medical said the frequently-cited study involved healthcare workers who experienced repeated virus exposure from close, often physical contact with infected patients. That the study showed cloth masks as less effective than medical-grade masks is not surprising, Schive said.
Other than frontline healthcare workers, Schive said, the study has little relevance to precautions that the average person should be taking.
“Remember, since the virus is spread through respiratory droplets, and since people are most contagious in the 48 hours before symptom onset, our cloth face coverings are meant to protect other people, not ourselves,” Shive said. “And there is steadily accumulating evidence that cloth masks perform that function well, by containing respiratory droplets before they can be expelled into the air.”
Mask use alone “not enough,” researchers say
One study often cited by critics, published April 6 in the journal Annals of Internal Medicine, involved asking four patients with COVID-19 to cough into a petri dish 7.8 inches away, then measured the viral load when patients wore cloth masks, surgical masks, and without a mask altogether. The South Korean researchers concluded that masks did not prevent infection.
But some researchers say they are hesitant to put much stock in the study because researchers didn’t look at other distances or check to see if droplets didn’t travel as far while people were wearing masks.
There are several real-world experiments that do tend to support mask use, according to MIT. In one early case, a man flew from Wuhan to Toronto with a dry cough and subsequently tested positive for COVID-19. He wore a mask during the flight, and no other passengers tested positive. In a more recent instance, two hair stylists employed in a newly reopened hair salon in Springfield, Missouri, worked on a combined 140 clients while sick with COVID-19. Everyone wore a mask per state order, and no clients tested positive.
In a May 21 perspective piece published in the New England Journal of Medicine, a group of five researchers concluded that universal masking alone is not enough to protect the public.
“A mask will not protect providers caring for a patient with active Covid-19 if it’s not accompanied by meticulous hand hygiene, eye protection, gloves, and a gown,” the authors state.
“A mask alone will not prevent health care workers with early Covid-19 from contaminating their hands and spreading the virus to patients and colleagues. Focusing on universal masking alone may, paradoxically, lead to more transmission of Covid-19 if it diverts attention from implementing more fundamental infection-control measures.”
