World facing multiple and evolving HIV epidemics, says UNAIDS

Roger Pebody
Published: 24 November 2009

A UNAIDS/WHO report has shown there are multiple and evolving HIV epidemics around the world.

The United Nations Project on HIV/AIDS (UNAIDS) and World Health Organisation (WHO) AIDS Global Epidemic update shows that sub-Saharan Africa remains the region most heavily affected by HIV. In addition, the number of new infections in Eastern Europe and Central Asia has increased massively since 2001, and HIV incidence amongst gay men remains high in western countries.

In 2008, sub-Saharan Africa accounted for 67% of the world’s HIV infections and 72% of AIDS-related deaths. However, the number of new infections was approximately 25% lower than in 1995.

The report notes the gains due to the scale-up of treatment but also notes disparities within the continent - coverage is estimated to be 48% in eastern and southern Africa, but 30% in west and central Africa (and much lower for children than for adults).

In terms of prevention programmes in Africa, the report notes a common failure to focus efforts on key groups such as older heterosexual couples, serodiscordant couples and people with HIV.

The report notes an evolution in the epidemic in Asia, with the epidemic steadily expanding into lower risk populations through transmission to the sexual partners of those who are most at risk (injecting drug users, sex workers and their clients, and men who have sex with men). Bangladesh is noted as transitioning from a low-level epidemic to a concentrated epidemic among injecting drug users.

Eastern Europe and Central Asia is the only region where HIV prevalence is thought to remain on the rise (a 66% rise from 2001). Ukraine and the Russian Federation are experiencing especially severe and growing national epidemics.

While injecting drug use remains the primary route of transmission in this region, in many countries, drug users frequently engage in sex work and transmit to other sexual partners. Access to antiretroviral therapy tends to be low, especially for injecting drug users.

In the Caribbean, the region with the highest prevalence outside Africa, it appears that the number of new infections is no longer declining, but has stabilised. The situation is also relatively stable in Latin America, but the report notes that although national epidemics in Latin America are heavily concentrated among men who have sex with men, injecting drug users and sex workers, only a small fraction of HIV prevention spending in the region supports prevention programmes specifically focused on these populations.

Turning to North America, Western Europe and Central Europe, although HIV incidence has either remained relatively stable or increased slightly in these countries in recent years, epidemiological patterns have evolved considerably. In particular, evidence indicates that the number of new HIV infections among men who have sex with men has increased in the past decade, while rates of new infections among injecting drug users have fallen. Ethnic minorities are more heavily affected by the epidemic than other populations.

The benefits of antiretroviral therapy have been particularly marked in these high income countries, with an estimated 7.2 million life-years added since 1996.

The report notes weaknesses in surveillance systems in many countries, but notes that this problem is especially acute in the Middle East and North Africa. A shortage of timely and reliable epidemiological and behavioural data hinders understanding of HIV-related dynamics and trends in this region.