89ºF

Trust Index: Do face masks reduce spread of coronavirus?

As requirements to wear face coverings grow, we look examine the facts

JACKSONVILLE, Fla. – There so much information circulating about coronavirus and a lot of data and studies -- sometimes with conflicting information -- is coming at us.

At Friday morning’s St. Augustine Commission meeting on a resolution requiring face coverings being worn inside buildings open to the public, comments from citizens included references to studies that showed 1) face masks are highly effective at minimizing the spread of the virus, 2) face masks make very little difference, and even 3) they are harmful because it causes you to breathe your own CO².

The Trust Index is here to help sort through those claims along with a photo circulating on social media that gives exact percentages of COVID-19 transmission when wearing a mask or not wearing one.

First: The medical community is in agreement that wearing masks is useful in limiting the spread of this virus. Quantifying how much it helps is the rub.

As to Friday morning public comments before the St. Augustine Commission vote to require masks, one person opposed to the resolution cited a New England Journal of Science study saying that masks don’t work. Apparently so many were citing this respected medical journal for information that masks aren’t effective, the journal posted a new article stating: “Universal masking helps to prevent such people from spreading virus-laden secretions, whether they recognize that they are infected or not.”

That information given to commissioners that masks make people breathe their own CO² has been widely debunked.

“Carbon dioxide molecules freely diffuse through the masks, allowing normal gas exchange while breathing,” emergency physician a Lenox Hill Hospital Dr. Robert Glatter told Healthline.

While people may not feel comfortable wearing a mask and many Americans just don’t think the government should tell them they have to wear one, every one of dozens of studies we found showed that masks provide at least some level of reduction in transmission of disease.

But don’t take our word for it. The Lancet on June 1 published an analysis of 172 studies from around the world and found that mask-wearing significantly reduces the risk of viral transmission.

Is that graphic real?

As for that illustration giving a percentage of likely spread of COVID-19 without masks, when one person wears one and when both wear one -- we asked one of UF Health Jacksonville’s top infectious disease experts about it. He’d said he’d seen it circulating online.

“There’s no site on it so there’s no ability to figure out who came up with this,” said Dr. Chad Nielsen, UF Health Jacksonville Director of accreditation in infection prevention. “Is it evidence-based or anything like that?”

News4Jax did a reverse image search and while we found it posted on dozens of websites -- including a couple of doctors and community hospitals -- there’s no clear source where it originated.

What about the percentiles it gives in each scenario? The graphic claims a 70% likelihood of transmission when a COVID-19 carrier is not wearing a mask, a 5% transmission risk with the coronavirus carrier was wearing a mask and a 1.5% level of transmission if both the carrier and the second person were both masked.

“I can’t verify that those are accurate because they didn’t give any citation for it,” Nielsen said. “That being the case, the intent of it is correct -- that masking does limit the spread of the disease amongst people.”

So while the intent of the graphic may be sincere, there’s no evidence the percentages are based on scientific data.

Bottom line: The Centers for Disease Control has recommended face coverings for months and still does.

As for specific claims, including the graphic you may have seen in your Facebook feed, we’re rating it a “Be Careful.”

Be Careful

After reviewing this topic, we've found some issues - Be Careful.

What is the Trust Index?


About the Authors: