Combination prevention approach could have a big impact on HIV epidemic in China

Increasing rates of HIV testing or expanding the use of antiretroviral therapy will not be enough to eliminate new HIV transmissions in China, according to a mathematical model published in the online edition of AIDS.

However, a “combination prevention” approach including an expansion of testing, targeted harm reduction programmes and wider use of HIV therapy was shown to have a potentially significant impact on the course of the epidemic in China.

“This is the first study to consider the cost-effectiveness of treatment, testing, harm reduction and combinations of these strategies at a national level in China,” write the authors. “Research to date has only considered the strategies in isolation and only in certain provinces and cities.”

At the end of 2009 there were an estimated 48,000 new HIV infections in China and the total number of infections in the country is thought to be in the region of 740,000.

The epidemic is concentrated in specific provinces (Yunnan, Guangxi, Guandong, Xinjiang and Henan) and focused on certain high-risk groups (injecting drug users, female sex workers and men who have sex with men).

A national government-led strategy advocates a comprehensive package of prevention, treatment and support as a way of controlling the epidemic. Nevertheless, the rate of testing among high-risk groups is generally low; there is limited access to harm reduction services such as needle exchange; and only a quarter of eligible patients are receiving antiretroviral therapy.

Given this situation, investigators wanted to gain a better understanding of the potential course of the HIV epidemic in China. They also wished to determine which of four prevention strategies would avert the greatest number of new infections and be most cost effective. The strategies were:

• Expanded voluntary couselling and testing (VCT).
• Expanded antiretroviral therapy: coverage of HIV treatment is increased to 50% of those eligible (CD4 cell count below 350 cells/mm³).
• Expanded harm reduction programmes: expanded to reach entire populations of injecting drug users.
• Combination strategies: a combination of any two or more of the above.

Cost-effectiveness was measured by calculating incremental quality-adjusted life years (QALYS) per life year gained.

The model predicted the course of the epidemic over 30 years.

The investigators’ calculations showed that without any new interventions, by 2040 the cumulative number of HIV infections in China would be 3.41 million. Three-quarters of these infections would be in high-risk groups. An estimated 25% of all injecting drug users would be HIV positive, whereas prevalence in men who have sex with men would reach 14%.

A VCT-only strategy, which involved annual HIV tests for high-risk individuals and one-off screening in lower-risk groups would avert an estimated 7% of all new infections at a cost of $5810 per QALY.

Expanding treatment would prevent an estimated 340,000 infections at a cost of  $4840 per QALY. A targeted harm-reduction programme would prevent 710,000 infections, costing $5010 per QALY.

“Biomedical interventions, such as VCT and treatment, can have a significant impact on HIV and are cost effective under certain implementation strategies,” comment the authors. However, they caution that, on their own, these interventions will not be able to eliminate HIV transmissions.

Combination prevention approaches were shown to have a bigger potential impact on the epidemic.

A combination of any two interventions would avert between 17 and 29% of new infections at a cost of between $5030 and $5310 per QALY. A combination of all three interventions – testing, treatment and harm reduction – was shown to avert 1.2 million new infections at an estimated cost of $5550 per QALY.

The investigators repeated their calculations to take account of the marginalisation of drug users and men who have sex with men in China. They believed that this would potentially make these high-risk groups harder to reach.

However, they showed that the combined use of all three methods of prevention could avert between 21 and 43% of projected infections over the next 30 years.

“This study shows that it may be possible to significantly control HIV growth amongst high-risk populations in China through a combination of VCT, treatment and harm reduction programmes,” conclude the authors. “These raise the possibility that China will face a future largely free of this disease if it acts now to implement a widespread expansion of both biomedical and harm reduction strategies.”