Vaccinating girls against human papillomavirus (HPV) is an ongoing public health campaign designed to prevent potentially life–threatening diseases, but use of the vaccine appears to be severely hindered by a prevailing belief that benefits are outweighed by potential disadvantages.
Two researchers at the Yale School of Public Health have studied how ongoing HPV vaccination efforts intersect with public psychology concerning adolescent promiscuity and everyday economics to persuade many parents and guardians not to have their children treated.
The Centers for Disease Control and Prevention recommends the HPV vaccination be administered to young females to protect against cervical cancer and genital warts. But currently less than 25 percent of the target population has received even one of the three recommended vaccinations, far below the target needed to maximize the vaccine’s potential public health benefit. An estimated 11,000 women in the United States alone were diagnosed in 2007 with invasive cervical cancer.
In the past, other health campaigns have been hampered by the public’s unwillingness to participate in sufficient numbers. The Yale researchers—Sanjay Basu, a Ph.D. candidate, and Alison Galvani, an assistant professor in the Division of Epidemiology of Microbial Diseases—said that the study suggests that educational programs that address specific public concerns might be needed to convince parents that the vaccine’s incentives outweigh other factors.
“A fundamental but often–neglected aspect of developing and implementing an optimal intervention program is human psychology which influences adherence to recommendations,” Galvani said.
The researchers applied “game theory” to the disease to create a mathematical model of how such external factors as a fear of encouraging promiscuity and money influence perceptions and ultimately affect public health goals. In the case of the HPV vaccine, the goal is to vaccinate girls between 11 and 12 years old (and also to administer catch–up vaccinations to females ranging from 13 to 26 years old).
Survey results showed that while the vast majority of respondents believed that the risk of cervical cancer and genital warts (which are largely spread through sexual contact) is far lower with the HPV vaccine. But the same group of 326 adults in the United States also thought that adolescent sexual activity would increase by a factor of 1.8 among those receiving the vaccine. Concerns about increased promiscuity were the single biggest factor in the decision–making process.
Financial considerations also influenced people’s choices. The research found that even with health insurance and other financial assistance, the average family still had to spend $181 out of pocket to provide a child with all three vaccinations. The researchers estimated that the price of each vaccination would have to be cut by $55 per dose to significantly influence decision making in favor of the vaccine.
Even if an individual’s perception on an issue such as HPV vaccination is not rational or well–informed, it is still a major factor in the decision–making process, the researchers said. If negative perceptions are widely held, the effectiveness of a public health campaign can be crippled.
Gretchen B. Chapman of Rutgers University also participated in the study. Details of the findings are printed in the Early Edition of the journal PNAS.