Introduction to the AIDS epidemic

The history of AIDS is a short one. As recently as the 1970s, no one was aware of this deadly illness. Since then the global AIDS epidemic has become one of the greatest threats to human health and development. At the same time, much has been learnt about the science of AIDS, as well as how to prevent and treat the disease.

The global picture

Statistics for the end of 2007 indicate that around 33 million people are living with HIV, the virus that causes AIDS. Each year around 2.7 million more people become infected with HIV and 2 million die of AIDS.

Although HIV and AIDS are found in all parts of the world, some areas are more afflicted than others. The worst affected region is sub-Saharan Africa, where in a few countries more than one in five adults is infected with HIV. The epidemic is spreading most rapidly in Eastern Europe and Central Asia, where the number of people living with HIV increased 150% between 2001 and 2007.

The spread of HIV and AIDS

AIDS is caused by HIV, a virus that can be passed from person to person through sexual fluids, blood and breast milk. Certain types of behaviour carry a higher risk of HIV transmission. People particularly vulnerable to HIV include injecting drug users, sex workers and men who have sex with men. In many people’s minds, HIV and AIDS are closely linked with these groups, which can lead to even greater prejudice against people already treated as outsiders.

Yet the vast majority of HIV infections are transmitted through sex between men and women. Nearly half of all adults living with HIV are female. Many Western countries, such as the UK, have increasing rates of HIV transmission through heterosexual sex. In America, where more than a million people are living with HIV, heterosexual sex accounts for one third of new diagnoses.

As a sexually transmitted infection, HIV particularly affects adolescents and young adults. Deaths of young adults have an especially damaging impact on their families and communities: skills are lost, workforces shrink and children are orphaned. In some African countries, life expectancies have fallen below 40 years, whereas they would have been above 60 without AIDS. There are around 15 million living children who have lost a parent to AIDS.

What can be done to combat the AIDS epidemic?

There is much that can be done to reduce the impact of AIDS, beginning with the prevention of HIV transmission. Averting sexual transmission involves encouraging safer sexual behaviour including delayed first sex, partner reduction and condom use. The spread of HIV through injecting drug use can be slowed by outreach work, needle exchanges and drug substitution treatment. And mother-to-child transmission can be almost eliminated through use of medicines and avoidance of breastfeeding.

There is still no cure for AIDS, but treatment for people with HIV has improved enormously since the mid-1990s. Those who take a combination of three antiretroviral drugs can expect to recover their health and live for many years without developing AIDS, as long as they keep taking the drugs every day.

Yet although it is known how to prevent and treat AIDS, few people have access to the necessary services. Most rich countries – and a few middle-income nations such as Brazil and Botswana – have achieved near-universal treatment coverage. But across the developing world only 31% of people who need anti-AIDS drugs are receiving them. Access to prevention tools such as HIV education, condoms, clean needles and programmes to prevent mother-to-child transmission is utterly inadequate. For example, in 2007 only 33% of pregnant women with HIV received the drugs that could stop their children becoming infected.

In recent years, efforts to fight AIDS around the world have stepped up, with much greater funding being supplied by the US, other rich nations and developing country governments. But the amount of money available is barely half what is needed for an effective response.


Apart from inadequate funding, major obstacles in tackling the global AIDS epidemic include weak infrastructure and shortages of health workers in the worst affected countries. Political or cultural attitudes are also significant: for example some authorities are opposed to condom promotion, while others refuse to support needle exchanges for injecting drug users. Many are reluctant to provide young people with adequate education about sex and sexual health.

Another very serious issue is stigma and discrimination. People known to be living with HIV are often shunned or abused by community members, employers and even health workers. As well as causing much personal suffering, this sort of prejudice discourages people from seeking HIV testing, treatment and care.

The future

Based on recent trends it is likely that AIDS around the world will keep getting worse for many years to come. Millions more will become infected with HIV and millions will die of AIDS.

The only way to turn things around is to rapidly scale up the measures we already know are effective, but which are currently reaching far too few of those in need.

In 2005 the world’s leaders pledged to try to achieve universal access to HIV prevention, treatment and care worldwide by 2010. This would be one of the greatest health achievements in history – saving millions of lives and giving new hope to suffering nations. But meeting this challenge will take bold leadership and a massive increase in effort; otherwise the promise is sure to be broken.