HIV VACCINES are considered the holy grail of AIDS research, yet the availability of one would not ensure that it would actually be taken by people at risk for HIV. “We know from vaccines for other diseases that mere availability is not sufficient,” says William Cunningham, M.D., professor of internal medicine and health-services research at UCLA. “The vaccine must be acceptable and accessible to people, particularly those at highest risk, in order to facilitate uptake.”
In a study of 1,100 high-risk adults published in Health Services Research, Dr. Cunningham and colleagues at the University of Toronto gave participants cards representing vaccines with various characteristics, such as 50-percent or 99-percent effectiveness; few or no side effects; costs of $10 or $250; and one-year or 10-year protection, and asked the participants to rate the acceptability of each. Participants also were asked to make trade-offs designed to determine those characteristics most important to them. For example, one card described a vaccine with 99-percent effectiveness but with minor side effects and a cost of $250, whereas another described a vaccine that was only 50-percent effective but has no side effects and cost only $10.
Participants were moderately accepting of an HIV vaccine overall, giving it a mean score of 55 on a 100-point scale, a finding that, while still positive, indicates that acceptability should not be taken for granted. Vaccine efficacy was the most important factor in boosting acceptability, followed by possible side effects and out-of-pocket costs. Also, 10 percent of at-risk adults indicated they would engage in more risky behavior if they were vaccinated. However, they were less likely to do so if the vaccine was only 50-percent effective versus 99-percent effective, suggesting they would adjust their behavior and expectations accordingly.