Almost 1 million people in Asia and the Pacific acquired HIV in 2002, bringing to an estimated 7.2 million the number of people now living with the virus – a 10% increase since 2001. A further 490 000 people are estimated to have died of AIDS in the past year. About 2.1 million young people (aged 15–24) are living with HIV.

With the exception of Cambodia, Myanmar and Thailand, national HIV prevalence levels remain comparatively low in most countries of Asia and the Pacific. That, though, offers no cause for comfort. In vast, populous countries such as China, India and Indonesia, low national prevalence rates blur the picture of the epidemic.

Both China and India, for example, are experiencing serious, localized epidemics that are affecting many millions of people.

India’s national adult HIV prevalence rate of less than 1% offers little indication of the serious situation facing the country. An estimated 3.97 million people were living with HIV at the end of 2001 – the second-highest figure in the world, after South Africa. HIV prevalence among women attending antenatal clinics was higher than 1% in Andhra Pradesh, Karnataka, Maharashtra, Manipur, Nagaland and Tamil Nadu.

New behavioural studies in India suggest that prevention efforts directed at specific populations (such as female sex workers and injecting drug users) are paying dividends in some states, in the form of higher HIV/AIDS knowledge levels and condom use. However, HIV prevalence among these key groups continues to increase in some states, underlining the need for well-planned and sustained interventions on a large scale.

The epidemic in China shows no signs of abating. Official estimates put the number of people living with HIV in China at 1 million in mid-2002. Unless effective responses rapidly take hold, a total of 10 million Chinese will have acquired HIV by the end of this decade – a number equivalent to the entire population of Belgium.

Officially, the number of reported new HIV infections rose about 17% in the first six months of 2002. But HIV incidence rates can soar abruptly in a country marked by widening socioeconomic disparities and extensive migration (an estimated 100 million Chinese are temporarily or permanently away from their registered addresses), with the virus spreading along multiple channels.

The most recent reported outbreaks of HIV among injecting drug users have been in Hunan and Guizhou provinces (where sentinel surveillance among users has revealed HIV prevalence rates of 8% and 14%, respectively). There are also signs of heterosexually transmitted HIV epidemics spreading in at least three provinces (Yunnan, Guangxi and Guangdong) where HIV prevalence in 2000 was as high as 11% among sentinel sex worker populations.

The onward sexual transmission of HIV by people who became infected when they sold their blood to collecting centres that ignored basic blood-donation safety procedures poses a massive challenge, as does the need to provide them with treatment and care. Signalling the gravity of the situation, one 2001 survey in rural eastern China found alarmingly high HIV prevalence – 12.5% – among people who had donated plasma. Most of the country’s estimated 3 million paid blood donors live in poor rural communities, and those now living with HIV/AIDS in provinces such as Henan (as well as Anhui and Shanxi, where similar tragedies might have occurred) face limited access to health-care services while having to endure severe stigma and discrimination.

There is a clear need for urgent action. By expanding prevention, treatment and care efforts across the entire nation, China can avert millions of HIV infections and save millions of lives in the coming decade. The five-year AIDS action plan promulgated in mid-2001 signalled a growing commitment to take up that challenge, as did the recent moves towards negotiating affordable antiretroviral treatment with pharmaceutical companies.

High HIV infection rates are being discovered among specific population groups (chiefly injecting drug users, sex workers, and men who have sex with men) in countries across the length and breadth of Asia and the Pacific.

Throughout the region, injecting drug use offers the epidemic huge scope for growth. Upwards of 50% of injecting drug users already have acquired the virus in parts of Malaysia, Myanmar, Nepal, Thailand and in Manipur in India, while HIV infections among Indonesia’s growing population of injecting drug users is soaring. Very high rates of needle-sharing have been documented among users in Bangladesh and Viet Nam, along with evidence that a considerable proportion of street-based sex workers in Viet Nam also inject drugs (a phenomenon detected in other countries, too). If the epidemic is to be stemmed, it is vital that injecting drug users gain access to harm reduction and other prevention services.

Male-to-male sex occurs in all countries of the region and features significantly in the epidemic. Countries that have measured HIV prevalence among men who have sex with men have found it to be high – 14% in Cambodia in 2000 and roughly the same level among male Thai sex workers. Homophobia or dominant cultural norms mean that many men who have sex with men hide that aspect of their sexuality. Many might marry or have sexual relationships with women.

Among the Pacific Island countries and territories, Papua New Guinea has reported the highest HIV infection rates. New surveillance data reveal an HIV prevalence of 1% among women attending antenatal clinics in the capital Port Moresby, indicating that a broadened epidemic is under way in the city. Among people seeking treatment for other sexually transmitted infections in the capital, HIV prevalence was 7% in 2001 (double the level in 2000). Very low levels of condom use and wide sexual networking (amid low awareness and knowledge of HIV/AIDS) means that the country could be facing a severe epidemic. Heightening that prospect are findings that 85% of surveyed sex workers in Port Moresby and in Lae did not use condoms consistently in 2001, and that rates of other sexually transmitted infections ranged as high as 36%. There is a dire need for rapid expansion of prevention efforts.

In Thailand, meanwhile, recent modelling suggests that the main modes of transmission have been changing. Whereas most HIV transmission in the 1990s occurred through commercial sex, half of the new HIV infections now appear to be occurring among the wives and sexual partners of men who were infected several years ago. There are also indications that unsafe sexual behaviour is on the increase among young Thais. This underlines the need to expand and revitalize strategies that can prevent this highly adaptable epidemic from spreading further in Thailand. In addition, adequate treatment and care should remain priority.

The Asian country with the highest adult HIV prevalence – Cambodia – has reported stabilizing levels of infection, along with still-decreasing levels of high-risk behaviour. HIV prevalence among pregnant women in major urban areas declined slightly from 3.2% in 1996 to 2.8% in 2002, according to the latest available data. Prevalence among sex workers declined from 42% in 1998 to 29% in 2002, according to the latest surveillance data, with the decline most pronounced among sex workers under 20. Given the high turnover of sex workers in Cambodia (almost three-quarters engage in sex work for less than two years), this steady decline suggests that prevention efforts focused on sex workers are yielding positive results among the succession of new entrants into sex work. Consistent condom use by sex workers appears to be the most important behavioural change achieved; it rose from 37% in 1997 to 90% in 2001.

Focussed efforts that protect vulnerable populations against HIV/AIDS are important and cost-effective. Alone, though, they cannot halt the epidemic. It is vital that AIDS responses everywhere extend also into the wider population, imparting the knowledge and providing the services that people need to protect themselves and each other against HIV/AIDS.

Given that many of the factors facilitating HIV transmission (including periodic economic upheaval and high rates of population mobility) are rife throughout this region, no country is immune to a rapidly spreading and wide-scale epidemic. Most countries, though, still have a window of opportunity for mounting and sustaining HIV/AIDS initiatives that could avert such an outcome.

Source: Joint United Nations Programme on HIV/AIDS (UNAIDS) and World Health Organization (WHO) 2002, AIDS Epidemic Update December 2002, Geneva.