Epidemiology

Epidemiology

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Worldwide: To date around 65 million people have been infected with HIV globally and 25 million people have died of AIDS since it was first recognised in 1981.

According to new data in the WHO AIDS epidemic update 2010, there were an estimated 2.6 million [2.3 million–2.8 million] people who became newly infected with HIV in 2009. This is nearly one fifth (19%) fewer than the 3.1 million [2.9 million–3.4 million] people newly infected in 1999, and more than one fifth (21%) fewer than the estimated 3.2 million [3.0 million–3.5 million] in 1997, the year in which annual new infections peaked.

In 33 countries, the HIV incidence has fallen by more than 25% between 2001 and 2009 (Figure. 2.2); 22 of these countries are in sub-Saharan Africa. In sub-Saharan Africa, where the majority of new HIV infections continue to occur, an estimated 1.8 million [1.6 million–2.0 million] people became infected in 2009; considerably lower than the estimated 2.2 million [1.9 million–2.4 million] people in sub-Saharan Africa newly infected with HIV in 2001. This trend reflects a combination of factors, including the impact of HIV prevention efforts and the natural course of HIV epidemics.

Several regions and countries do not fit the overall trend. In seven countries, the HIV incidence increased by more than 25% between 2001 and 2009. In Western, Central, and Eastern Europe, Central Asia, and North America, the rates of annual new HIV infections have been stable for at least the past five years. However, evidence is increasing of a resurgence of HIV in several high income countries among men who have sex with men. In Eastern Europe and Central Asia, high rates of HIV transmission continue to occur in networks of people who inject drugs and their sexual partners.

More information is available from the WHO website at: http://www.unaids.org/documents/20101123_GlobalReport_em.pdf

In 2009, the Health Protection Agency (HPA) estimated there were about 86,500 people of all ages with HIV living in the UK. Approximately 26% of these are undiagnosed and thus are unaware they are infected with HIV. During 2009, there were 6,630 new diagnoses of HIV in the UK. This represents a fourth year-on-year decline, largely due to fewer diagnoses among people infected heterosexually abroad, mostly in Sub-Saharan Africa.

New diagnoses among men who have sex with men remained high in 2009, and four out of every five probably acquired their infection in the UK.

Wales: In Wales up until the end of June 2010, there have been 1796 individuals diagnosed with HIV infection. However, this number may change due to the delay in receiving some reports.

The HPA reported 142 new diagnoses of HIV infection in Wales in 2009 and is relatively stable when compared to 2008 when 149 new diagnoses were reported. The highest number of new diagnoses in Wales since the start of the epidemic was recorded in 2007 at 188. Twenty-two new AIDS diagnoses and eleven deaths from an AIDS-related illness were reported from Wales in 2009.

During the 1980s and 1990s, newly diagnosed HIV positives were most frequently men who reported sex with other men (MSM). However the number of infections in patients reporting sex between men and women as their most likely source of infection has increased sharply in recent years.

In Wales during 2009, the percentage of new diagnoses probably acquired by heterosexual contact was 37% (53 of 142 new diagnoses) and the number aquired through sex between men was 54% (76 of 142).