Cowpox vaccine is a smallpox vaccine. In ancient times there have been inoculated cowpox to prevent the practice of smallpox, this is because the cowpox virus and smallpox virus have the same surface protein antigen, and the cowpox virus infection is very small damage to the human body, after infection with cowpox virus, the body will be infected with cowpox virus according to the surface antigenic markers to produce the appropriate antibodies, these antibodies also have a strong killing power of smallpox, so the human body after the smallpox virus also has a Therefore, the human body is also resistant to smallpox virus. Cowpox vaccine is actually smallpox vaccine, which is a biological agent used to prevent smallpox virus infection. However, since there are no more smallpox patients in China at present, cowpox vaccine is generally not administered.