HIV-1 refers to Human Immunodeficiency Virus Type 1, which is the most common and widespread type of HIV that infects humans. HIV-1 is the virus responsible for causing the majority of HIV infections globally. Research in the area of HIV-1 focuses on understanding the virus's mode of transmission, replication, genetic diversity, and interactions with the immune system. This research also aims to develop effective treatments, vaccines, and prevention strategies to combat the spread of HIV-1 and improve the quality of life for those living with the virus.