Question: I was just reading that WHO recommends people ages 60+ and people with underlying comorbidities should wear a “medical mask” in settings where physical distancing cannot be achieved. My parents fit that criteria, so I wanted to buy them some medical masks to supplement the cloth masks they are currently using. But then I got confused — is there a difference between medical masks and surgical masks? Is any mask that looks like a doctor’s mask (you know the blue pleated ones) a “medical mask”? With so many options not to choose from, I’m struggling to know the difference!

Answer: Interesting question that caused me to revisit the WHO Guidance and FDA approvals, thanks! Longer answer follows, but in short:

• Medical masks and surgical masks are different! Unlike medical masks, surgical masks must meet more regulatory requirements regarding fluid penetration and flammability requirements. (Note: I do not believe that they necessarily *look* different)
• Please avoid purchasing surgical masks as there are still healthcare personal protective equipment supply issues and we should save the surgical masks (and N95s) for health care personnel.
• When it comes to shopping for medical masks, the main thing to pay attention to is ASTM or EN-rating. If the mask meets either ASTM F2100 or EN 14683 ratings, it has performance characteristics recommended by WHO.

Now the details. First up, Figure 1 is the WHO definition of “medical mask.” Here, to be called a “medical mask,” specific performance characteristics must be met. When it come to performance characteristics, WHO specifies ASTM F2100, which is the American Society for Testing and Materials (ASTM) set of specifications for “classifications, performance requirements, and test methods for the materials used in the construction of medical face masks”, and EN 14683, which is the European Standard. Importantly, the WHO definition makes “fluid penetration resistance” optional, which means that ASTM F2100 Level 1 masks (as opposed to Level 2 or 3) are appropriate for your parents to use (Figure 2).

In the United States, all medical devices are regulated by the FDA, which *typically* means that in order to be designated a “medical” or “surgical” mask, the mask must receive FDA approval. Due to the COVID public health emergency, we are in *atypical* times and FDA has therefore eased regulatory approvals for face masks. Under the FDA’s emergency use authorization (EUA), “face masks for a medical purpose that are not intended to provide liquid barrier protection” can be manufactured and marketed without FDA notification and do not have to comply with certain regulatory requirements. Meanwhile, FDA calls those face masks that are intended to provide fluid penetration resistance “surgical masks.” Surgical masks must meet additional ASTM standards and flammability requirements, though under the EUA, surgical masks can also be manufactured and marketed without FDA notification and do not have to comply with certain regulatory requirements. All face masks that are being manufactured and marketed under the EUA must “clearly and conspicuously state that the product has not been FDA cleared or approved, the product has been authorized by FDA under an EUA…” I raise this in the context of shopping — if you’re on Amazon and see this type of statement, it’s not necessarily an indictment on the product being sold, rather the product is new and following EUA guidelines.

Note: CDC offers this infographic on surgical mask and N95 mask differentiation and FDA offers this description (Figure 3).

Figure 1. WHO “Medical Mask” Definition

Figure 2. ASTM Levels of Mask Protection (from Cardinal Health Face Mask Selection Guide)

Figure 3. FDA Surgical Mask Description (from FDA)