I first came to China more than 15 years ago. At that time, China was just starting to come to terms with the HIV epidemic, and scale up its response. Not long after that, the first methadone clinics were opened. The early days of China's HIV response were filled with hard and bitter lessons. But they showed me firsthand what China can achieve when it sets its mind to overcoming a challenge.

The HIV epidemic in China was driven initially by injecting drug use. China's response: set up a massive national network of needle exchanges and methadone centres. There are now 763 clinics across the country. China is a world leader in this. The result: A marked reduction of HIV prevalence among people who inject drugs.

I am heartened by the incredible progress China has made since the first outbreaks of AIDS. Compared to my early days, China is now much better placed to prevent HIV infection, and doing better at caring for those living with HIV. Yet as we recognize World AIDS Day, I know there is much more China needs to do.

It is time to bring the same spirit of pragmatism and innovation which created a world's best practice methadone treatment program to the challenges with HIV that we confront in China today. Chief among these is the fact that the HIV epidemic in China is now largely driven by sexual transmission - in particular among men who have sex with men, where HIV infections are on the rise. But the heterosexual population is not immune: HIV infections are not decreasing in this population either.

We must do better than this, starting with making safe sex "sexy"! We need to find new, interesting, innovative, effective ways of promoting safe sex in China, especially including condom use. Because every new HIV infection is one too many; every new infection is one that could have been avoided.