- A new study finds that people who have an infection with the new coronavirus can transmit it to others nearby by simply speaking.
- The study affirms that 6 feet of distance between people while speaking may not be enough to prevent transmission.
- In public places, researchers say wearing a mask with a tight fit and a face shield is the best protection from the coronavirus, especially for workers who can’t maintain physical distance to do their jobs.
As COVID-19 vaccines continue to roll out across the United States, more areas are looking to reopen businesses for in-person services, from indoor dining and haircuts to manicures and church services.
While we gain steps toward prepandemic times, one rule will surely linger: wearing a face mask while inside those buildings.
Dr. Anthony Fauci, the U.S. premiere expert on infectious diseases, said it’s “possible” that people could still be wearing masks into 2022 in the United States, as masks remain a simple and effective way to help protect people from the new coronavirus and other pathogens.
But under what circumstances we’re wearing those masks and other personal protective equipment remain to be fully seen.
New research provides some very specific information on how respiratory droplets travel when someone is merely speaking — not sneezing, coughing, or singing, which so much other research has focused on.
A person with a coronavirus infection can transmit virus by simply talking
A new study published in the journal Physics of Fluids shines more light — well, lasers, actually — on how respiratory droplets travel during normal conversation, affirming that sometimes 6 feet of distance while speaking may not be enough.
Researchers from Aoyama Gakuin University and Yamano College of Aesthetics in Japan tested real-world scenarios where typical physical distancing guidelines are impossible to follow.
They used lasers to visualize droplets after a study participant inhaled from a vaping device and then spoke the word “onegaishimasu,” a typical Japanese greeting in a business setting.
The participants did so in different positions and postures commonly found in the service industry, such as a person getting their hair washed at a salon or lying facedown or faceup, as is common in medical exam rooms or nursing homes.
“A significant amount of similar face-to-face contact would occur not only in cosmetology but also in long-term and medical care,” said Keiko Ishii, a study author, doctor of engineering, and associate professor at Aoyama Gakuin University, in a press release.
Researchers found some pretty predictable outcomes: Droplets from an unmasked person go out and down, so if a customer or patient is lying below, they’ll be covered in those droplets and could contract the coronavirus if the speaker has an infection.
But even by wearing a mask in that scenario doesn’t completely protect the would-be customer or patient.
The researchers say that while sitting or standing and wearing a mask, a person’s leaked aerosol cloud tends to cling to their body due to their body heat, but the cloud detaches when they lean over someone and falls on the person below.
The researchers found that a mask and face shield combination kept any aerosols leaked from the edges of the mask from dropping to the person below.
“The face shield promoted the rise of the exhaled breath,” Ishii said. “Hence, it is more effective to wear both a mask and a face shield when providing services to customers.”
The researchers' overall conclusion — wearing a mask and face shield is the best protection from the new coronavirus — isn’t that shocking, especially for workers who can’t physically distance to do their jobs.
“I’m not sure it changes anything regarding policy,” said Thomas LaVeist, PhD, dean of Tulane University School of Public Health and Tropical Medicine, who wasn’t part of the study.
Dr. Jagdish Khubchandani, professor of public health at New Mexico State University, who also wasn’t part of the study, said it was a “rich” study that helps better explain the transmission trajectories of infectious disease agents, especially in everyday settings.
“The novelty is that even talking and breathing can be a risk to individuals around us given the force that we use in breathing and talking and the result of exhalation,” he said. “This study helps build a case for masks and shields as much as we can use them.”
How to protect yourself
This is also especially important as more contagious forms of the coronavirus mutate and spread, whether from abroad or in the United States — which is why the Centers for Disease Control and Prevention (CDC) in February reminded people that mask fit is important.
Some CDC guidelines include wearing two masks to ensure they form a tight seal around your face.
While masks and face shields are common sights in the healthcare setting — especially during a pandemic — they may be more common as hair salons, barbershops, and nail salons reopen their doors for business while the COVID-19 pandemic continues.
Study highlights why risk of exposure remains high for frontline workers
The study does add to the growing body of research on how to best protect frontline and essential workers, which overwhelmingly are people of color.
“Who gets to work from home all day on Zoom and still get paid?” said LaVeist, whose work examines the social and behavioral factors that explain race differences in health outcomes.
Frontline workers are often doing so inside spaces that are notoriously cramped, such as restaurant kitchens and meat-packing plants.
A University of California, San Francisco study released in January found that among essential workers, cooks, line workers in warehouses, agricultural workers, bakers, and construction laborers were more likely to die from COVID-19.
Examining death certificate data in California, the study also found Latino food and agriculture workers experienced a 59 percent increase in death, Asian healthcare workers experienced a 40 percent increase, and Black retail workers saw a 36 percent increase.
In comparison, white food and agricultural workers only saw a 16 percent increase in death.
Numbers like these highlight the inequalities facing essential workers, pointing to the need for proper personal protective equipment, especially in settings when physical distancing is impossible to do the job properly.
“A face shield isn’t that expensive,” LaVeist said. “If you are going to open and put people in danger, you have an obligation to ensure your employees are safe.”