Any mask worn to protect against COVID-19 infection or prevent its spread should consist of two layers and fit well over both the nose and mouth. This includes cloth masks for personal use, medical-grade masks used at work and N95 respirators used for high-risk patient interactions.
All medical-grade isolation and surgical masks comprise more than one layer of material. The most common medical-grade masks contain three layers: an outer fluid-repellent layer, an inner absorbent layer and an additional middle layer that varies by manufacturer and intended use.
Because medical-grade masks already contain multiple layers of barrier, wearing two masks is not recommended, nor has it been shown to provide additional protection against the virus.
Additionally, wearing two medical-grade masks complicates the removal or “doffing” process and can actually create an increased risk for exposure if not doffed correctly. It can also create user discomfort with increased pressure at ear lobes and additional layers to breathe through.
A single medical-grade isolation mask provides appropriate protection. All N95 respirators also contain multiple layers of barrier protection against the virus, negating the need for an additional mask.
To keep our staff protected at work, continue current practices and wear a multi-layer, well-fitting mask that covers the nose and mouth, at all times.