region where HIV/AIDS is common
1 The vast majority of people living with HIV are in low-and middle-income countries. 2  According to WHO, sub-Saharan Africa is the most affected region, with 24.7 million people living with HIV in 2013.3  Seventy-one percent of all people who are living with HIV in the world live in this region.he Global HIV/AIDS Epidemic. HIV, the virus that causes AIDS, is one of the worldâs most serious health and development challenges: 1  According to the World Health Organization (WHO) ,