1.Infections through sexual behavior:
Having unprotected oral, anal, vaginal sex, or other types of bodily fluid exchange with an HIV-infected person are at risk for HIV infection.

2.Infections through blood:
(1)Transfusion of or contact with HIV-contaminated blood, or plasma products
(2)Sharing needle and syringes with HIV-infected intravenous drug users
(3)Transplant of organs from HIV-infected sufferers

3.Vertical mother-to-child transmission:
Infants may be infected through its HIV-infected mother during pregnancy, childbirth, or breast-feeding.

Behavior unlikely to get HIV-infected
Kiss, mosquito stings, activities in daily lives such as hand-in-hand, hug, having meals together, using the same toilet seat, swimming, and attending classes are unlikely to become HIV-infected. HIV will not be able to enter human body through intact, uninjured skin.

Will using the same toothbrush, razor, or tooth extraction, acupuncture, earlobe piercing, and fine hair removing from face with two interweaving threads transmit HIV ?
Since the use of toothbrush and razor may cause bleeding, sharing toothbrush and razor may become HIV-infected. Tooth extraction, acupuncture, earlobe piercing, and fine hair removing from the face with two interweaving threads may also cause bleeding or direct contact between apparatus and bodily fluids. As a result, if given the chance, they will be able to transmit AIDS. However, strict compliance with apparatus sterilization procedures will reduce the risk for infections.

What are the symptoms of HIV infection?
According to surveys conducted by National Taiwan University Hospital, symptoms of HIV infections often seen in Taiwan include fevers, diarrhea, loss of body weight, cough, and mouth moniliasis.

What is asymptomatic period? Is it infectious during this period?
After HIV infection, it will take certain period of time for antibody to develop. Since antibody yet detectable during early stage after the infection, standard laboratory tests show HIV negative. This is what we call the asymptomatic period or "window period." Generally speaking, the initial 6 to 12 weeks after exposure to HIV is the asymptomatic period, during which the amount and communicability of HIV virus are both highest.

Having had highly risky behavior for HIV infections, what should be done?
Some behavior is more risky than others including having sex with sex workers, having unprotected anal sex, having multiple sexual partners, having another sexually transmitted disease, having sex with an HIV-infected person or intravenous drug users, and sharing needles/syringes. Once having any of the above, the one should go to a hospital designated by Department of Health to receive a test. No matter what the result is, risky behavior should be ceased.