HIV is a virus that infects the immune system and is transmitted through bodily fluids. The main ways HIV can be transmitted are through unprotected sex, sharing needles, blood transfusions, and from mother to child during birth or breastfeeding. People can protect themselves by using protection during sex, not sharing needles, getting tested before having a baby, and avoiding contact with other people's blood. HIV is not transmitted through everyday contact like using the bathroom, coughing, or sweat.