Although HIV antibodies are negative during the window period, the HIV virus is already present in blood, semen, vaginal secretions, cerebrospinal fluid, chest and abdominal fluid, amniotic fluid, breast milk and other bodily fluids, so this is also a dangerous time for people who do not know they have AIDS but are already infectious. The window period is usually 2-4 weeks after HIV infection, but in some cases it can be as short as one week or as long as three months. After the window period, the acute phase of AIDS will be followed by symptoms of HIV viremia, mainly febrile symptoms, and often swollen lymph nodes.