We agree with Udo Schuklenk (A vaccine for AIDS – Is it time to concede defeat?, Globe and Mail Update, June 19, 2008) that it is definitely ‘not’ time to concede defeat in the search for new ways to prevent HIV infection and pull the plug on vaccine and microbicide trials. But Mr. Schuklenk’s commentary includes misinformation about vaccine and microbicide trials.

His claim that “more than 150 recent prevention trials, including vaccine and microbicide candidates, failed to protect trial participants against HIV infection” is incorrect. While there have been more than 150 clinical trials of HIV prevention interventions over the last decade, the vast majority of them have been small-scale safety and dosing trials, not large-scale efficacy trials. To date, only three vaccine candidates and five microbicide candidates have been tested – or are currently being tested – in large-scale efficacy trials.

The nature of biomedical research is that more candidates – as many as 8 or 9 in 10 products – will fail in human testing. If researchers had given up on finding treatment and prevention options for other diseases after a handful of failures, we would have far fewer options in healthcare today. In the 1930s, two experimental polio vaccines failed because they were determined to be unsafe, and polio vaccines were almost abandoned. But we needed new tools then, just as we need new tools now.

Mr. Schuklenk also says that microbicide trials have achieved only “an increase in the number of women who have become more susceptible to HIV infection as a result of their trial participation.” While it is true that two microbicide trials and one vaccine trial were stopped because the candidates being tested appeared to increase some participants’ chances of becoming infected with HIV, the vast majority of trial volunteers – tens of thousands of men and women around the world – have safely participated in vaccine and microbicide trials that have provided important information for researchers to move the field forward. Also, we would add the often forgotten fact that by participation in the trials, many people actually avert potential infections because of the safer sex counseling, condom provision and the treatment of other sexually transmitted infections.

We wholeheartedly agree with Mr. Schuklenk’s argument that we need to focus on ethical concerns and protection of trial participants, and those protections exist in current clinical trials. The AIDS Vaccine Advocacy Coalition, Global Campaign for Microbicides, and African Microbicides Advocacy Group all work with researchers, communities, trial volunteers and policymakers around the world to ensure that the rights of trial participants are protected and trials are conducted ethically.

The bottom line is that, despite recent setbacks, we must maintain momentum in HIV prevention research, including both vaccine and microbicides, while simultaneously continuing to ramp up provision of existing treatment and prevention options for all those who need them. Mr. Schuklenk is correct in saying that we should never give up on looking for ways to end the AIDS epidemic.