HIV and AIDS are both major public health issues in many countries around the world, and it’s really important to keep track of how the epidemic is spreading and how effective interventions are. The Sustainable Development Goals (SDG 3.3.1) and the 2021 United Nations Political Declaration set targets to lower new HIV infections. The number of new HIV cases per 1,000 uninfected people shows how much the virus is being transmitted in a population. There are several ways to measure the HIV infection rate based on the epidemic setting. Even though measuring incidence directly at the population level is better, it is often difficult to obtain. Due to this limitation, most countries use indirect methods or a combination of both direct and indirect data to measure the incidence rate.