AIDS belongs to category B infectious diseases, and China’s new law on the prevention and control of infectious diseases divides infectious diseases into three categories, namely, A, B and C, with a total of 39 types. Among them, there are 2 types of infectious diseases in category A, namely plague and cholera; 26 types of infectious diseases in category B, including AIDS, infectious atypical pneumonia, highly pathogenic avian influenza, hepatitis B, tuberculosis, measles, poliomyelitis, anthrax, diphtheria, whooping cough and tetanus, etc. The most common are influenza, parotid fever and other infectious diseases, and the most common are influenza. There are 11 types of infectious diseases in category C, including influenza, mumps, hand-foot-mouth disease and so on.