Estimating the Demand for a Preventive HIV Vaccine: Why We Need to Do Better

A t the end of 2005, about 40 million people worldwide were living with HIV/AIDS, most of them adults and 95 percent of them living in developing countries. Although vigorous prevention programs are under way in many countries, about 3 million people still died from AIDS in 2005 and more than 13,000 people became infected with HIV every day [1]. Hence there is an urgent need for stronger and more effective HIV prevention. New technologies are required to augment existing prevention methods. An HIV vaccine could make an enormous difference in the effort to reverse the pandemic, thereby saving tens of millions of lives. Vaccines have been highly cost-effective in fi ghting other infectious diseases such as polio, smallpox, hepatitis B, yellow fever, and a range of childhood illnesses. A safe, effective, and accessible preventive HIV vaccine would be a hugely valuable addition to the existing array of prevention measures. In a number of modeling exercises, analysts have shown that even a partially effective vaccine could decisively lower the rate of new infections, averting millions of new infections each year [2–4]. In the global effort to develop an HIV vaccine, more than 30 vaccine candidates are currently in trials in 19 developed and developing countries [5]. Among these, a large-scale phase III trial is under way in Thailand, and a major phase IIb trial involving several thousand volunteers is ongoing in Latin America, the Caribbean, Europe, and North America to obtain proof of concept for a vaccine built on an adenovirus vector platform [6]. The results of these trials over the next few years will help us set a more defi nitive timeline for the eventual launch and introduction of a vaccine. For a vaccine to make a difference in halting the AIDS pandemic, it needs to be widely available and accessible, and must be taken up. The vaccine must be demanded by individuals and government authorities. Reliable estimates of demand for an HIV vaccine would help in achieving several policy and advocacy objectives related to this goal, including: (1) persuading governments and industry to invest more in research and product development; (2) convincing donors to fi nance vaccine purchases, in advance or at the time of uptake, given the limited ability of governments and individuals in poor developing countries to pay for a vaccine; (3) helping industry to determine the scale of manufacturing facilities to build to ensure adequate …