Is a Face Shield Effective Against COVID-19? Study Reveals It Might Not Be

Many Filipinos noticed that while other countries only use face masks to protect themselves against the SARS-CoV-2 virus, the Philippines resorted to having “another layer of protection” in the form of face shields. But is a face shield effective against COVID-19? Engineer Joshua Agar, an assistant professor from the University of the Philippines, conducted a simulation study to find the answer.

PH Policies on Face Shields: A Timeline

Before we talk about Engineer Agar’s simulation study, which aims to shed some light on the question, “Is a face shield effective against COVID-19?”, let’s first look back on the government’s policies regarding face shields.

Last year, the PH government required the public to wear a face shield. This was along with a face mask. Both are requirements when riding public transportation or entering establishments, such as malls.

But in December 2020, they released another statement. In it, they said that full face shields (those that cover the face from forehead to chin) were mandatory in public places. These supposedly “effectively lessen the transmission of COVID-19.” This is in response to the possibility of increased transmission due to the holiday season. 

The President himself eased the policy this year, stating that face shields should only be used in hospitals and healthcare institutions. But just a few days later, the government retracted their decision. They said the plastic covering is still mandatory indoors and outdoors.

Face Shield Use Is Questionable for Many People, Including Experts

Since no other country requires face shields on top of masks, many Filipinos ask this question: Is a face shield effective against COVID-19?

The Department of Health issued a statement reiterating the fact that no single method can provide full protection against the SARS-CoV-2. Still, they said face shields “provide another layer of protection against it.”

Some experts, however, need more convincing. One concerned citizen conducted a simulation study to determine how particles behave when a person is wearing a face shield.

Engineer Agar’s Simulation Study

Is a face shield effective against COVID-19? Wind Engineer Joshua Agar’s experiment explores the particles’ behavior against a face shield.

In two scenarios, Engr. Agar explained that while shields redirected the flow to the side, they still formed vortices, which means particles have been deposited at the back of the shield. This indicates the face is already involved, and that if a person is not wearing a face mask, there would be a greater chance of contracting the virus.

Engr. Agar also said the situation is worse if the person is facing sideways from the source of the virus.

In a third scenario, the simulation study showed shields could pose an even greater danger in an area where the virus is already present in the air.

Despite the experiment’s potential, Engr. Agar said he wouldn’t be publishing it due to financial constraints. Still, he mentioned he is willing to join other experts in studying the face shield effect.

WHO To Study PH’s Experience With Face Shields

Is face shield effective against COVID-19? The World Health Organization would like to know, too. And they said they would look into the country’s experience with face shields.

Dr. Rabindra Abeyasinghe, WHO representative to the Philippines, admitted that while the Philippines sort of delayed the speed of Delta variant spread, they still do not know if face shields are a contributing factor.

The WHO likewise said face shields reduce the likelihood of transmission through the eyes. “That’s not actually an additional layer although it actually boosts the protection provided by poor mask-wearing practices,” Dr. Abeyasinghe said.

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