Availability of vaccine no guarantee public will want it

The research -- which looked at acceptability of potential future HIV vaccinations among high-risk adults in Los Angeles -- shows many factors come into play when a person is deciding whether or not be vaccinated.

"As we can see in the current climate of confusion around H1N1 flu shots, the availability of a vaccination alone is not enough to encourage people to be inoculated," says lead author Peter A. Newman, associate professor at UofT's Factor-Inwentash Faculty of Social Work and Canada Research Chair in Health and Social Justice. "Our study shows the same holds true when it comes to potential HIV vaccines down the road. Even in the case of a safe and highly effective vaccine, there are a plethora of factors that impact peoples' decisions."

To determine what factors would make a vaccine "acceptable" to individuals at-risk of contracting HIV, Newman and his team gave each of 1,100 participants a set of nine cards outlining theoretical HIV vaccines. Each card described a theoretical HIV vaccine with a different combination of characteristics, including vaccine effectiveness, cost and side effects. Participants were then asked to rate the "acceptability" of each vaccine according to what vaccine characteristics were most and least important to them.

The team found a moderate level of acceptability for a future HIV vaccine -- 55 on a 100-point scale. But while the moderate level of acceptability is positive, Newman says their results indicate that not everyone -- including those in high-risk communities -- would automatically accept an HIV vaccine in the event that one was developed.

The factors that most influenced participants' acceptance of the theoretical vaccines were efficacy (how effective a vaccine would be against HIV) followed by side effects and cost. The team also found that about 10 percent of at-risk adults might increase their sexual risk behaviours -- such as not using condoms -- if vaccinated against HIV.

"Merely having a vaccine available doesn't mean it gets to the people who need it -- a fact that is evidenced by the issues we're seeing now around H1N1 vaccines," says Newman. "If we want HIV vaccines to be acceptable and accessible to people, we need to consider all of these factors before we have a safe and relatively effective vaccine on the market."

Education is key, says Newman. People need to trust that a vaccine is good and will be effective. They need to understand in lay terms how it works. They need to know what scientists mean when they talk about a vaccine's efficacy, and they need to know they shouldn't increase their risk behaviours simply because they're being vaccinated. Initial HIV vaccines may be only partially effective in preventing HIV infection; they may be a great addition to existing prevention methods, but not a replacement.

The research also indicates that governments should consider how to subsidize vaccines to make sure they are affordable to those who are least able to pay.

Newman says the study provides a template that should be replicated in the developing world, which carries 95 percent of the global HIV burden.

"In order to ensure future HIV vaccines are acceptable to those who need them, we must start acting now," says Newman. "Formative research that aims to anticipate and address consumer preferences and larger challenges in the introduction of new health and prevention technologies is a cost-effective means to promote success."