title: Global epidemiology of HIV.
abstract: OBJECTIVE
  To provide an update on the epidemiology of HIV worldwide and by region, along with an overview of recent HIV epidemiological research.
  
  
  RESULTS
  The global prevalence of HIV-1 has stabilized at 0.8%, with 33 million people living with HIV/AIDS, 2.7 million new infections, and 2.0 million AIDS deaths in 2007. Heterosexual spread in the general population is the main mode of transmission in sub-Saharan Africa, which remains the most heavily affected region, with 67% of the global burden. Male-male sex, injection drug use, and sex work are the predominant risk factors in most other regions. Infection rates are declining in some regions, including some of the most heavily affected countries in Africa, but climbing elsewhere such as in eastern Europe and central Asia. Recent HIV epidemiologic research findings include new insights into the role of HIV viral load, co-infection with sexually transmitted infections, male circumcision, antiretroviral treatment, serosorting, and superinfection in HIV transmission and prevention.
  
  
  CONCLUSIONS
  The global prevalence of HIV has stabilized in this decade, but with important regional differences in trends and modes of transmission. Prevention and treatment programs have an expanding impact in preventing HIV infection and AIDS deaths.
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. pbk4@cdc.gov
authors.forename: Peter H
authors.initials: PH
authors.lastname: Kilmarx
mesh_terms: D000349:Africa / Q000453:epidemiology; D001209:Asia, Central / Q000453:epidemiology; D035843:Biomedical Research / Q000639:trends; D005061:Europe, Eastern / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification; D006801:Humans; D008297:Male; D015995:Prevalence