The new study, conducted by a government-backed research center in Japan, found that face shields do not stop the spread of COVID-19 without a mask covering underneath.
Results from the study reportedly proved that nearly 100 percent of airborne droplets less than 5 micrometers in size escaped through the plastic shields. In addition, about half of larger droplets measuring 50 micrometers found their way into the air, the Guardian reported.
Makoto Tsubokura, a team leader at Riken, strongly recommended that regular face masks be used instead of plastic face shields for protection from the virus.
“Judging from the results of the simulation, unfortunately the effectiveness of face guards in preventing droplets from spreading from an infected person’s mouth is limited compared with masks,” he told the Guardian.
Tsubokura also said that those who have been advised to not wear face masks, such as people with respiratory issues or young children, can use face shields instead — but only outdoors or in properly ventilated indoor areas.
The Centers for Disease Control and Prevention has also recommended wearing cloth facial coverings as opposed to face shields to help stop the spread of the virus.
While the United States has reported the most confirmed cases and deaths due to COVID-19, many states have reported declining cases due in part to local mask mandates.
South Carolina’s Department of Health and Environmental Control officials reported in August that areas where mask mandates are in place have “seen an overall decrease of 15.1 percent of total cases,” while cases in areas without a mask mandate rose by up to 30.4 percent.
Health officials in Kansas have reported similar findings, sharing that while new cases had dropped in counties with a mask mandate in place, there had been no decrease in areas without one.
“All improvements in case development comes from those counties wearing masks” Dr. Lee Norman said at a press conference last month, according to the Associated Press.
As of Wednesday, Sept. 23, there are at least 6.9 million cases of COVID-19 in the U.S., while over 200,000 people in the country have died from coronavirus-related illnesses, accoding to the NYT‘s database.