Masks provide some protection against some airborne viruses, but not against viruses transmitted by other means. There are many ways for viruses to spread, and different types of viruses have different ways of spreading, common ways of spreading include airborne, bloodborne, sexually transmitted, fecal-oral transmission and so on. Masks can prevent air containing viruses from entering the human respiratory tract through the nose and mouth, thus preventing infection of viruses, so they have a certain degree of protection against airborne viruses, such as the new coronavirus, influenza virus, etc., but the protective effect of masks is also limited. However, the mask has no defense ability against viruses spread in addition to other ways, such as hepatitis B virus, HIV can be transmitted through blood and sexual transmission, hepatitis A virus can be transmitted through fecal-oral transmission, at this time, even if you wear a mask can not play a preventive role. In addition, it should be noted that, when choosing a mask, you should choose surgical masks and other protective masks, not cotton masks, etc., otherwise the same can not resist any virus.