The window period of AIDS is when a person has a high-risk behavior, such as blood or body fluid contact with the patient’s blood or body fluid, which leads to the invasion of the virus into the human body. However, after the virus has invaded the body, it takes a period of time to detect HIV infection through current testing methods, such as blood tests for viral nucleic acid or HIV antibodies. The window period can be long or short: firstly, it depends on how virulent the virus is. Secondly, it also depends on how strong the immunity is. If we check the antibodies of HIV, the immunity of each person is different, and the antibodies produced may be early for some people and late for others. Thirdly, it is also related to the testing method used. The nucleic acid test is generally available in about 2 weeks, while the antibody test may be available in about 4 weeks. If it is an antigen test, some may be 2-3 weeks. The various different testing methods also result in a window period that may out extended or short. It does not mean that there is no virus in the body during the window period, only that the amount of virus is small and we may not be able to detect it, and it does not mean that it is not infectious. It does not prove that you are not infected with HIV. Therefore, only after the window period, through effective testing methods can we find out whether there is HIV infection.