SAN FRANCISCO Although development of an HIV vaccine would save many lives, the vaccine could negatively affect many others, according to a new study. Those who think they are safe from disease because of a vaccine may choose a risky lifestyle.
Development of an HIV vaccine raises psychosocial and behavioral questions that must be identified and addressed before a vaccine campaign could be successful, according to Patrick Webb, MS, who spoke at the 29th Annual Society for Adolescent Medicine meeting recently held here.
A highly efficacious vaccine could result in decreased condom use and an increase in sexual partners, leading to unintended pregnancies, increases in sexually transmitted diseases (STDs) and possibly even an increase in HIV, said Webb, author of the study.
The study also revealed that the efficacy of HIV immunization would impact adolescents' willingness to receive the vaccine. Based on the study results, adolescents would most likely not use HIV vaccines of limited efficacy, said Webb, psychology fellow in the section of adolescent medicine, Indiana University School of Medicine.
"As work has progressed on developing an HIV vaccine, one of the key concerns has been that any HIV vaccine that is developed may have an efficacy level as low as 50%," Webb said. "However, prior research indicates that people may not accept a vaccine of limited efficacy."
Webb and his colleagues presented adolescents with questions concerning hypothetical HIV vaccines of 50% and 90% efficacy. Adolescents were asked what the expected response would be to a hypothetical HIV vaccine with a 90% efficacy level; what the response might be to a 50% efficacious vaccine and; what effect a 90% efficacy level would have on sexual behaviors.
There was a striking difference in the percentage of adolescents who endorsed an acceptance of the hypothetical HIV vaccine of 90% efficacy compared with the acceptance of the hypothetical vaccine of 50% efficacy. While 89% of the adolescents endorsed acceptance of the more efficacious vaccine, only 28% endorsed acceptance of the lesser efficacious vaccine. "Even those tended to be ambivalent," Webb said.
Webb also presented examples of typical adolescent responses to each of the vaccines. Most responses to the 50% efficacious vaccine concluded that receiving the vaccine would be useless, and no more effective than using a condom.
Common example responses included: "There would be no sense in getting it ... it would be just like using a condom," and "They would not get it because of the 50-50 chance they could still get AIDS."
However, 77% of the adolescent sample indicated they anticipated an increase in risky sexual behavior as a result of taking the 90% efficacious HIV vaccine. Only 14% of the sample reported that people would engage in less frequent risky sexual behavior, and 9% of the sample responded that people would not change their risk behaviors.
Common example responses to the 90% efficacious vaccine included: "They wouldn't use condoms and would go wild having more sex," and "They would go around having sex with anyone and everything."
"These behavioral consequences would lead to implications for HIV immunization planning in terms of additional counseling and an integration of more comprehensive sex education into the program," Webb said.
Sex education should be approached in a thoughtful and comprehensive manner, and should include the many psychosocial, behavioral and medical issues associated with sexual behavior. The pervasive use of AIDS as a "scare tactic" in sex education interventions is "misguided and shortsighted," he said.
Diffusion theory may provide a guide toward understanding the responses of the sample adolescents and assist in understanding the implications presented in the study.
This theory proposes that any innovation must be viewed by adolescents as having an advantage over existing technology; therefore, HIV immunization must be viewed by adolescents as having an advantage over condoms.
The study sample clearly did not view the 50% efficacious vaccine as an improvement over condoms, thus HIV programs must anticipate the probability of this nonacceptance of vaccine of limited efficacy and develop interventions to clarify the benefits of vaccine acceptance over nonacceptance.
"If these efforts are successful, diffusion theory might predict then that if adolescents could accept these benefits as having an advantage for them over the conditions of the existing technology of condoms, they would accept the vaccine," Webb said.
The subject sample consisted of 140 adolescents who were receiving health care at urban community adolescent health clinics; 83% were blacks and 81% were female. Ages of participants ranged from 13 to 18 years, with an average age of 16.
For more information:
- Webb P, Zimet G, Fortenberry JD. Having sex with anyone and everything; anticipated reactions to HIV immunization. Presented at the 29th Annual Society for Adolescent Medicine meeting. March 5-9. San Francisco.
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