There are many types of vaccines, but all generally work by teaching the immune system to recognize and fight back against a disease-causing microorganism. Some vaccines are designed to help the immune system prevent an infection and are called preventive vaccines. Others are therapeutic vaccines, designed to help people who already have a disease to clear the infection. Currently, there are no effective HIV vaccines of either kind.
Studies at the HVTN focus on preventive vaccines. Vaccines used in HVTN studies are made in the lab. Because we do not use the actual virus, you cannot get HIV from being in one of our studies.