Wearing a mask can help lower the risk of respiratory virus transmission. When worn by a person with an infection, masks reduce the spread of the virus to others. Masks can also protect wearers from breathing in infectious particles from people around them. Different masks offer different levels of protection. Wearing the most protective one you can comfortably wear for extended periods of time that fits well (completely covering the nose and mouth) is the most effective option.
Generally, masks can help act as a filter to reduce the number of germs you breathe in or out. Their effectiveness can vary against different viruses, for example, based on the size of the virus. When worn by a person who has a virus, masks can reduce the chances they spread it to others. Masks can also protect wearers from inhaling germs; this type of protection typically comes from better fitting masks (for example, N95 or KN95 respirators).
There are many different types of masks that have varying abilities to block viruses depending on their design and how well they fit against your face. Cloth masks generally offer lower levels of protection to wearers, surgical/disposable masks usually offer more protection, international filtering facepiece respirators (like KN95 respirators) offer even more, and the most protective respirators are NIOSH Approved® filtering facepiece respirators (like N95® respirators).
All of the prevention strategies described in this guidance can be helpful to reduce risk. They are especially helpful when:
CDC offers separate, specific guidance for healthcare settings (COVID-19, flu, and general infection prevention and control). Federal civil rights laws may require reasonable modifications or reasonable accommodations in various circumstances. Nothing in this guidance is intended to detract from or supersede those laws.
