New data show global HIV prevalence - the percentage of people living with HIV - has levelled off and that the number of new infections has fallen, in part as a result of the impact of HIV programmes.
However, in 2007 33.2 million [30.6 - 36.1 million] people were estimated to be living with HIV, 2.5 million [1.8 - 4.1 million] people became newly infected and 2.1 million [1.9 - 2.4 million] people died of AIDS.
There were an estimated 1.7 million [1.4 - 2.4 million] new HIV infections in sub-Saharan Africa in 2007—a significant reduction since 2001. However, the region remains most severely affected. An estimated 22.5 million [20.9 - 24.3 million] people living with HIV, or 68% of the global total, are in sub-Saharan Africa. Eight countries in this region now account for almost one-third of all new HIV infections and AIDS deaths globally.
Since 2001, when the United Nations Declaration of Commitment on HIV/AIDS was signed, the number of people living with HIV in Eastern Europe and Central Asia has increased by more than 150% from 630 000 [490 000 - 1.1 million] to 1.6 million [1.2 - 2.1 million] in 2007. In Asia, the estimated number of people living with HIV in Viet Nam has more than doubled between 2000 and 2005 and Indonesia has the fastest growing epidemic.
These findings were released by the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization (WHO) in the report 2007 AIDS Epidemic Update.
The new report reflects improved and expanded epidemiological data and analyses that present a better understanding of the global epidemic. These new data and advances in methodology have resulted in substantial revisions from previous estimates.
While the global prevalence of HIV infection—the percentage of people infected with HIV— has levelled off, the total number of people living with HIV is increasing because of ongoing acquisition of HIV infection, combined with longer survival times, in a continuously growing general population.
Global HIV incidence—the number of new HIV infections per year—is now estimated to have peaked in the late 1990s at over 3 million [2.4 - 5.1 million] new infections per year, and is estimated in 2007 to be 2.5 million [1.8 - 4.1 million] new infections, an average of more than 6 800 new infections each day. This reflects natural trends in the epidemic, as well as the result of HIV prevention efforts.
The number of people dying from AIDS-related illnesses has declined in the last two years, due in part to the life prolonging effects of antiretroviral therapy. AIDS is among the leading causes of death globally and remains the primary cause of death in Africa.
“These improved data present us with a clearer picture of the AIDS epidemic, one that reveals both challenges and opportunities,” said UNAIDS Executive Director Dr Peter Piot. “Unquestionably, we are beginning to see a return on investment—new HIV infections and mortality are declining and the prevalence of HIV levelling. But with more than 6 800 new infections and over 5 700 deaths each day due to AIDS we must expand our efforts in order to significantly reduce the impact of AIDS worldwide.”
UNAIDS, WHO and the Reference Group on Estimates, Modelling and Projections have recently undertaken the most comprehensive review of their methodologies and monitoring systems since 2001. The epidemic estimates presented in this year's report reflect improvements in country data collection and analysis, as well as a better understanding of the natural history and distribution of HIV infection. This information is vital in helping countries understand their epidemics and respond to them more effectively.
UNAIDS and WHO are now working with better information from many more countries. In the past few years a number of countries, most notably in sub-Saharan Africa and Asia, have expanded and improved their HIV surveillance systems, conducting new, more accurate studies that provide more precise information about HIV prevalence than earlier studies. In addition, 30 countries mostly in Africa have conducted national representative population-based household surveys. These have also informed adjustments for other countries with similar epidemics that have not conducted these surveys. New assumptions have also been made as a result of a better understanding of the natural history of untreated HIV infection.
The current estimate of 33.2 million [30.6 - 36.1 million] people living with HIV replaces the 2006 estimate of 39.5 million [24.5 - 47.1 million]. Applying the improved methodology retrospectively to the 2006 data, the 2007 report revises that figure, now estimating that in 2006 there were 32.7 million [30.2 - 35.3 million] people living with HIV. The single biggest reason for the reduction in global HIV prevalence figures in the past year was the recent revision of estimates in India after an intensive reassessment of the epidemic in that country. The revised estimates for India, combined with important revisions of estimates in five sub- Saharan African countries (Angola, Kenya, Mozambique, Nigeria, and Zimbabwe) account for 70% of the reduction in HIV prevalence as compared to 2006 estimates.