Fact check: Document does not show official CDC guidance on face masks

By Reuters Staff

6 Min Read

Social media posts show a photograph of a document carrying the logo of the U.S. Centers for Disease Control and Prevention (CDC) that does not recommend the use of face masks. The document has not been released by the CDC and contains misleading information about the effectiveness of masks in preventing the spread of COVID-19.

Posts sharing the document can be seen here and here. The document features a CDC letterhead and text that claims N95 masks, surgical masks and cloth masks are either dangerous or do not prevent the spread of COVID-19.

When asked if the document was authentic, the CDC told Reuters that it does not typically issue guidance or recommendations to the public in such a format.

The agency said its guidance and recommendations are distributed on the agency's website (www.cdc.gov/), official social media accounts and through news media.

In the first paragraph, the document states that the CDC does not recommend that the public uses N95 masks. While this is true, the CDC explains that this is because critical supplies should be reserved for healthcare workers and other first responders, not because the masks are ineffective as the document suggests (here).

The document goes on to say that the N95 masks are designed to not filter exhaled breath because they are designed for contaminated environments.

This is true (see 3M's FAQ here) but only for respirators fitted with valves, which open to release exhaled breath and close to filter inhaled breath. CDC guidelines explain that a N95 respirator with a valve provides "the same level of protection to the wearer as one that does not have a valve". Because of this, the agency advises that respirator with a valve should not be used in situations where a sterile environment must be maintained, such as an operating room, because the valve allows "unfiltered exhaled air to escape into the sterile field" (here).

The second part of the document claims that "particles and contaminants" in the environment can clog surgical masks, rendering them useless. "If you come in contact with COVID, your mask TRAPS IT, YOU become a walking virus dispenser", it reads.

According to the CDC, surgical masks protect against "large-particle droplets splashes", while also protecting others from the wearer's respiratory emissions(here).

Surgical masks do not, however, block or filter very small particles in the air that may be transmitted by coughs or sneezes (here).

Surgical masks can therefore trap some, but not all, particles that could carry the SARS-CoV-2 virus if the wearer is exposed to a carrier.

The Food and Drug Administration (FDA) further advises: "Surgical masks are not intended to be used more than once. If your mask is damaged or soiled, or if breathing through the mask becomes difficult, you should remove the face mask, discard it safely, and replace it with a new one. To safely discard your mask, place it in a plastic bag and put it in the trash. Wash your hands after handling the used mask.

Finally, the document argues that cloth masks are a health risk because they trap CO2, and that the moisture trapped in the masks can make them "mildew ridden" in 30 minutes.

The Reuters Fact Check team previously debunked the claim that masks cause the wearer to breath in dangerous amounts of CO2 (here).

At the time, a representative from the U.S. Centers for Disease Control and Prevention (CDC) told Reuters: "The CO2 will slowly build up in the mask over time. However, the level of CO2 likely to build up in the mask is mostly tolerable to people exposed to it. You might get a headache but you most likely [would] not suffer the symptoms observed at much higher levels of CO2".

On April 3, 2020, the CDC updated its previous advice and recommended people to wear cloth face coverings "in public settings when around people outside their household, especially when social distancing measures are difficult to maintain."(here) (here)

The CDC does not advise a time limit for when face coverings should be removed but does recommend that they should be washed after each use(here).

False. This document was not published by the CDC and contains incomplete and misleading information about the effectiveness of masks. Currently the CDC advises that medical masks should be reserved for healthcare workers, but that the general public should wear cloth face coverings to help prevent the spread of COVID-19.

This article was produced by the Reuters Fact Check team. Read more about our work to fact-check social media posts (here).

Our Standards: The Thomson Reuters Trust Principles.