Fever can occur during the window period of HIV. Around 2-4 weeks after the initial HIV infection, a part of the infected patients will have clinical symptoms due to the viremia of HIV as well as the impaired immune function of the body, of which fever is the most typical symptom. Fever during the window period is not particularly high, and often shows only a low fever, with a temperature of about 38℃, not exceeding 38.6℃. The fever is accompanied by general malaise, headache, night sweats, diarrhea, muscle aches, joint pains, skin rashes, swollen lymph nodes and so on, which are often mild and can be relieved on their own after about 1-3 weeks. In fact, during this period of time, most patients can already be diagnosed by blood tests for HIV-RNA and P24 antigen.