As I just witnessed during my recent visit here, China has made substantial progress in checking the spread of HIV but there is still a long way to go. From an infection unknown only 27 years ago, AIDS has become truly globalized. Today, 33 million people live with HIV around the globe, and 25 million more have died.

These figures are sobering. However, it is important to note that we have entered a new phase in responding to AIDS - a phase that will ultimately be far more challenging than anything we have done so far.

Now, for the first time, the AIDS response is producing real results.

In 2007, fewer people got newly infected and the number of people dying of AIDS worldwide dropped, mainly thanks to better access to antiretroviral treatment.

In China, over 34,000 people are now taking HIV drugs, up from 5,000 in 2003. But, we cannot slow down in our vigilance. Whereas substantial progress has been achieved in this country, the number of people receiving HIV drugs is still less than half the number who require them. The epidemic continues to run ahead of the response: for every two people who start taking antiretroviral drugs, another five become newly infected with HIV.

Many of those infections occur in situations that are illegal or outside of mainstream society. These give rise to apparent contradictions between respect for the law and protecting the health of people who inject drugs or are sex workers, between sexuality and morality, between needs of public security and public health, drug control and safe injections. Indeed, to confront AIDS is to confront contradictions in society.

On closer investigation, however, most of these contradictions prove to be false contradictions. A scientifically-based AIDS response can solve them for the greater wellbeing of more people.

Drug abuse, for example, is bad for an individual's health and for the community he or she lives in. HIV infections are particularly high among people who inject drugs. Laws against drugs must be respected to protect society.

Ultimately, though, the best way to protect both the wider population and drug users, and at the same time reconcile public security and public health concerns is to adopt the "harm reduction" approach. Scientific evidence - including here in China- shows that providing drug users with substitution therapy and clean needles reduces HIV transmission and supports enforcement of laws against drug abuse.

Similarly, working with sex workers and their clients to encourage condom use reduces HIV among these groups and in society as a whole. When such programs are backed up by poverty reduction efforts to reduce women's need to engage in prostitution, their impact is even greater.

It is issues such as these that make AIDS such a complex problem to deal with. Complex problems require complex solutions. They also respond best to collective approaches. Working with community groups, for example, can greatly increase the impact - and effectiveness - of AIDS strategies. In fact, given that most infections are happening in situations outside the mainstream norm, it is often very difficult for government alone to reach those who need to be reached.

It is encouraging, therefore, to note that there has recently been an increase in the number of community organizations working on AIDS in China. Many of these groups are doing incredible work.

The Joint Assessment Report published last year by the government together with the United Nations System clearly highlights the need for greater involvement of community-based organization in the roll-out of programs to reach people with relevant services.

Currently, there are no easy ways for community-based organizations to register. Without registration, there can be no bank account and thus no easy way to receive funding. Many of the groups I have seen are doing a great job - but their work is based on volunteerism. This is neither efficient nor sustainable.

China has solid policies in place and has made significant progress in the fight against AIDS. It is time now to use the tremendous array of resources at its disposal to build on that progress, and to tackle new, tough challenges like harm reduction and increasing civil society involvement,

As Chairman Mao said more than 60 years ago: "We must not become complacent over our success. We should check our complacency and constantly criticize our shortcomings, just as we should wash our faces and sweep the floor every day to remove the dirt and keep them clean."