Abstract
Understanding where adolescents obtain information about human papillomavirus (HPV) vaccines may be helpful in designing public health interventions promoting HPV vaccination. This study assessed the following: (1) exposure to specific sources of information about HPV vaccines, (2) self-reported helpfulness of these sources of information, and (3) whether the specific source of information was associated with knowledge and perceptions about HPV vaccines among adolescent girls. There were 339 adolescent girls (mean age = 16.8 years) recruited into the study. Television advertisements, the Internet, doctors/nurses, and mothers were the most frequently reported sources of vaccine information; more than 90% of participants who received information from these sources reported they were helpful. Adolescents who received information about HPV vaccines from television advertisements, the Internet, clinicians, and mothers had higher knowledge about HPV vaccines and more positive perceptions. Assuring the accuracy of messages from these sources will be essential, given their importance in influencing adolescents’ knowledge and perceptions about HPV vaccines.
Introduction
Currently, 3 vaccines, a bivalent, quadrivalent, and 9-valent vaccine, are recommended by the Advisory Committee on Immunization Practices for prevention of infection by human papillomavirus (HPV), a virus that is causally linked with anogenital cancers and condylomata.1,2 The Advisory Committee on Immunization Practices recommends routine HPV vaccination for boys and girls aged 11 to 12 years, catch-up vaccination for males aged 13 to 21 years as well as vaccination of males aged 22 to 26 years at high risk, and catch-up vaccination for females aged 13 to 26 years. 1 However, current HPV vaccination rates in the United States fall short of Healthy People 2020’s objective of 80% coverage for adolescents aged 13 to 15 years. 3
HPV vaccine uptake has been associated with higher HPV knowledge, more perceived benefits of vaccination, fewer perceived barriers to vaccination, greater perceived susceptibility to HPV-related disease, and belief that influential individuals would recommend vaccination.4,5 Despite the importance of knowledge and perceptions in vaccine uptake, little is known about the factors associated with higher knowledge or positive perceptions toward HPV vaccination, especially among adolescent girls. Therefore, determining factors associated with HPV vaccine knowledge and perceptions among adolescents is of interest as interventions affecting change in knowledge and perceptions are needed to increase uptake. 6
Individuals, especially parents and clinicians, are likely to influence adolescent girls’ vaccine knowledge and attitudes.7,8 Adolescents tend to have positive attitudes about HPV vaccination when their parents intend to vaccinate them and when adolescents perceive that their parents think vaccination is important.7,9 Likewise, provider recommendation for vaccination is a critical factor in terms of vaccine acceptability for parents as well as adolescents.10-13 However, the influence of adolescents’ social networks and media on knowledge and perceptions toward the HPV vaccine among adolescent girls have not been examined, to our knowledge.
While mass media is useful in providing information and helping people construct knowledge about the vaccine, the interpersonal interactions of the social network have the potential to be more effective in forming and changing health behavior perceptions.14,15 For example, if the HPV vaccine is perceived to be risky by parents and adolescents, information provided through websites, presentations, printed public health materials, and one-on-one counseling may lack the required components needed to persuade parents and adolescents to accept and obtain the HPV vaccine.16,17 Additionally, family members and friends as sources of information have been documented to negatively influence vaccination behaviors; for example, if they share negative experiences of the influenza vaccine making them sick. 18 Thus, HPV vaccine acceptance may be dependent on parents and adolescents obtaining accurate information and positive messages from multiple sources including mass media and people within their social networks.
Therefore, we designed a study among adolescent girls who had received their first HPV vaccine to (1) examine exposure to specific sources of information about HPV vaccines among adolescent girls, specifically media and people within adolescents’ social networks; (2) assess self-reported helpfulness of these sources of information; and (3) determine whether the specific source of information, as well as the number of sources of information, were associated with knowledge and perceptions about HPV vaccines.
Material and Methods
Subjects and Study Design
Participants, aged 13 to 21 years, were consecutively recruited from an urban hospital-based adolescent primary care office for a longitudinal study examining the attitudinal and behavioral impact of HPV vaccination among adolescent girls. The data analyzed for this study were collected at the baseline visit. The study was approved by the hospital’s institutional review board.
Participants completed self-administered, paper-and-pencil surveys. The survey included a 13-item validated index assessing knowledge about HPV (10 items) and HPV vaccines (3 items; Table 1). 19 Response options were true, false, and don’t know, and scale score was calculated for the number of correct items. The survey also assessed HPV vaccine perceptions of normative beliefs, benefits, and barriers, and perceptions of HPV severity and susceptibility using validated, theory-based scales developed in our previous work among similar populations.19-21 The 7 scales, each including items measured using a 5-point Likert-type rating, assessed normative beliefs (belief that influential people would want the participant to be vaccinated; 4 items, Cronbach’s α = .72), barriers to vaccination related to vaccine safety (4 items, α = .74), barriers related to insufficient information about the HPV vaccine (2 items, α = .88), benefits of vaccination related to vaccine safety (3 items, α = .80), benefits of vaccination related to protection against HPV-related disease (2 items, α = .60), perceived susceptibility to genital warts and cervical cancer (2 items, α = .75), and perceived severity of genital warts and cervical cancer (2 items, α = .84).
HPV and HPV Vaccine Knowledge.
Abbreviations: HPV, human papillomavirus; Pap test, Papanicolaou test.
Correct answer = False.
Correct answer = True.
Vaccine-related knowledge item.
Participants were asked to indicate whether they had heard about HPV vaccines during the prior 6 months from any of the following sources: 4 media sources (newspaper/magazine, television [TV] advertisements, radio, and the Internet), and 7 individual network sources (mother, father, other relatives, doctor or nurse, teacher, church/synagogue/mosque, and girlfriends or boyfriends). If the participant reported that she heard about HPV vaccines from a given source, she was asked to rate the source as extremely helpful, somewhat helpful, or not helpful to her. Given that only a small percent of participants endorsed any source as somewhat helpful, the 3 categories were collapsed for analysis into not helpful versus somewhat or extremely helpful.
Statistics
Descriptive analyses were performed to examine participants’ demographic characteristics, sources of information about HPV vaccines, HPV and HPV vaccine knowledge and perceptions. Univariate analyses using independent t tests were performed to compare the mean scores for knowledge and perceptions scales for those who did versus those who did not report having received information about HPV vaccines from each of the 11 possible sources of information. Spearman correlation coefficients were used to determine whether the number of sources of information reported was associated with knowledge and perceptions scale scores.
Results
Demographics
The mean age of the 339 participants was 16.8 years, and the majority was black (n = 259, 76.4%), followed by white (n = 56, 16.5%) and other (n = 24, 7.1%). Most participants reported having insurance at the time of enrollment (n = 284, 83.7%) with Medicaid as the primary source (n = 194, 57.2%). Just more than half of the participants were sexually experienced (n = 195, 57.5%). Table 1 provides the percentage of participants who responded correctly to the HPV and HPV vaccine knowledge scale. Table 2 provides sources of information about HPV vaccines and helpfulness of each source.
Sources of Information About HPV Vaccines and Helpfulness of Each Source.
Abbreviations: HPV, human papillomavirus; TV, television.
Associations Between Sources of Information and Knowledge and Perceptions Toward HPV Vaccines
TV advertisements, in addition to being the most commonly reported media source for HPV vaccine information, were also associated with several knowledge and perceptions measures (Table 3). Having received (vs not having received) information from a TV advertisement was associated with higher knowledge (t = 5.05, P < .0001), higher normative beliefs (ie, belief that important individuals would want her vaccinated; t = 2.90, P = .004), fewer perceived barriers related to vaccine safety (t = 2.55, P = .011), greater perceived benefits related to vaccine safety (t = 3.05, P = .0024), and greater perceived benefits related to vaccine protection (t = 2.75, P = .0062). In contrast, TV advertisements were associated with lower perceived susceptibility to genital warts and cervical cancer (t = 1.98, P = .049). Having received information from the Internet was associated with higher HPV knowledge (t = 3.23, P = .0014), and having received information from the Internet (t = 2.06, P = .04) and a newspaper (t = 4.08, P < .0001) were also associated with higher normative beliefs.
Association Between Sources of Information About HPV and HPV Vaccines and Knowledge and Perceptions Regarding HPV Vaccines.
Abbreviation: HPV, human papillomavirus.
Measured using a 13-item validated index assessing knowledge about HPV (10 items) and HPV vaccines (3 items). Response options included true, false, and don’t know with scale scores being calculated on the number of items correct. Higher scores indicate higher knowledge of HPV and the vaccine.
Measured the belief that influential people would want the participant to be vaccinated. Four items were used in this scale and response options included a 5-point Likert-type rating. Higher scores indicate higher normative beliefs.
Measured perceived barriers to vaccination related to vaccine safety using 4 items. Response options included a 5-point Likert-type rating, and higher scores indicate fewer barriers to vaccination based on vaccine safety.
Measured perceived barriers related to insufficient knowledge about the HPV vaccine using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate fewer barriers because of insufficient information about the HPV vaccine.
Measured perceived benefits to vaccination related to vaccine safety using 3 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived benefits to vaccination based on vaccine safety.
Measured perceived benefits of vaccination related to protection against HPV-related disease using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived benefits to vaccination based on protection against HPV-related disease.
Measured perceived susceptibility to genital warts and cervical cancer using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived susceptibility.
Measured perceived severity of genital warts and cervical cancer using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived severity.
P < .0001. ***.0001 ≤ P < .001. **.001 ≤ P < .01. *.01 ≤ P < .05.
Doctors and nurses were the most commonly reported individual source of information about HPV vaccines and the individual source associated with the highest number of scales measuring knowledge and perceptions. Those who indicated that doctors or nurses were sources of information had higher knowledge scores (t = 1.98, P = .049), higher normative beliefs (t = 2.22, P = .027), fewer perceived barriers related to vaccine safety (t = 3.27, P = .0012), and greater perceived benefits related to vaccine safety (t = 2.34, P = .02). Participants who reported mothers as a source of information had higher normative beliefs (t = 2.45, P = .015) and fewer perceived barriers related to vaccine safety (t = 1.98, P = .048). In contrast, the few participants who endorsed fathers as a source of HPV vaccine information had lower knowledge about HPV and HPV vaccines (t = 2.25, P = .025) and fewer perceived benefits related to vaccine safety (t = 3.84, P = .0001).
Spearman correlation coefficients between number of information sources reported and knowledge and perceptions are shown in Table 4. Greater number of media sources was associated with higher knowledge (rs = .22, P < .0001), higher normative beliefs (rs = .20, P = .0002), fewer perceived barriers related to vaccine safety (rs = .17, P = .0023), greater perceived benefits related to vaccine safety (rs = .14, P = .0083), and greater perceived severity of genital warts and cervical cancer (rs = .13, P = .02). Higher number of individual sources was associated with higher normative beliefs (rs = .15, P = .0067) and fewer perceived barriers related to vaccine safety (rs = .15, P = .005). Higher number of total sources was associated with higher knowledge (rs = .16, P = .0025), higher normative beliefs (rs = .21, P < .0001), fewer perceived barriers related to safety (rs = .17, P = .0013), and greater perceived benefits related to safety (rs = .13, P = .0201) and vaccine protection (rs = .13, P = .0165).
Spearman Correlation Coefficients Between Multiple Sources of Information With Knowledge and Perceptions About HPV and HPV Vaccines.
Abbreviation: HPV, human papillomavirus.
Measured using a 13-item validated index assessing knowledge about HPV (10 items) and HPV vaccines (3 items). Response options included true, false, and don’t know with scale scores being calculated on the number of items correct. Higher scores indicate higher knowledge of HPV and the vaccine.
Measured the belief that influential people would want the participant to be vaccinated. Four items were used in this scale and response options included a 5-point Likert-type rating. Higher scores indicate higher normative beliefs.
Measured perceived barriers to vaccination related to vaccine safety using 4 items. Response options included a 5-point Likert-type rating, and higher scores indicate fewer barriers to vaccination based on vaccine safety.
Measured perceived barriers related to insufficient knowledge about the HPV vaccine using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate fewer barriers because of insufficient information about the HPV vaccine.
Measured perceived benefits to vaccination related to vaccine safety using 3 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived benefits to vaccination based on vaccine safety.
Measured perceived benefits of vaccination related to protection against HPV-related disease using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived benefits to vaccination based on protection against HPV-related disease.
Measured perceived susceptibility to genital warts and cervical cancer using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived susceptibility.
Measured perceived severity of genital warts and cervical cancer using 2 items. Response options included a 5-point Likert-type rating, and higher scores indicate greater perceived severity.
Media sources included between 0 and 4 sources.
Individual sources included between 0 and 7 people as sources.
Total sources included between 0 and 11 media and people as sources.
P < .0001. ***.0001 ≤ P < .001. **.001 ≤ P < .01. *.01 ≤ P < .05.
Discussion
Media sources were highly associated with knowledge about HPV and the vaccine. Media can have a powerful impact on vaccination attitudes and behaviors as demonstrated by negative media coverage of the measles-mumps-rubella vaccine leading to decreased measles-mumps-rubella vaccination. 22 Given that media and marketing can be biased and can influence knowledge and perceptions, it was encouraging that in this study exposure to TV advertisements was associated with greater HPV and HPV vaccine knowledge and more positive perceptions toward the vaccine. This finding correlates with another study’s results that women in the United States demonstrated better understanding of HPV than women in the United Kingdom and Australia; this finding was hypothesized to be related to the direct-to-consumer advertisements by the manufacturer, which are not allowed in the United Kingdom or Australia. 23 While our study demonstrated positive results regarding exposure to TV advertisements, additional data are needed to better understand the relationship between TV advertisements and HPV vaccine perceptions and uptake.
This study also demonstrated that obtaining information about the HPV vaccine from the Internet was associated with higher knowledge and positive normative beliefs. While an increasing number of people utilize the Internet to obtain information about the HPV vaccine,24,25 websites that are critical of the vaccine enhance negative perceptions and lower vaccination intention.26,27 Therefore, the participants in this study might have accessed an Internet website providing positive messages about the HPV vaccine. However, people searching the Internet for vaccine information are likely to experience a mix of accurate and inaccurate information. Thus, public health officals should include efforts to help parents and adolescents to distinguish Internet sites that provide medically accurate, evidence-based information from those based on misinformation and myths, 28 thereby increasing positive perceptions of HPV vaccines and intention to vaccinate.
Additionally, analyses suggest that exposure to more than one media source was associated with increased knowledge and more positive perceptions. Several studies of adults have demonstrated that greater volumes of media coverage as well as multiple sources of HPV information, including media and people from social networks, were correlated positively with HPV knowledge29,30; one found that for each additional source reported, there was a greater odds of having received the vaccine or intention to get the vaccine for themselves (in those vaccine eligible) or for their daughter (if a parent). 29 Despite these efforts, more than one fifth of sixth graders’ parents who did not receive the vaccine reported that they did not have enough information about the vaccine to make an informed decision. 5 Furthermore, other studies examining online news stories31-33 have found key concepts about HPV vaccines to be missing, such as HPV’s link to cervical cancer, risk factors, symptoms, and common prognosis. Thus, it is important that media sites providing health information are monitored and have mechanisms in place to provide accurate and comprehensive information. Furthermore, one study utilized a social marketing approach to better understand how to provide HPV vaccine information to African American girls and their mothers. These participants suggested using several channels of communication, including mass media to provide information about safety and side effects, how HPV is spread, and where to receive more information. Participants also suggested these messages should be catchy yet simple and designed by teens. 34 More research is needed to explore whether media messages that influence perceptions and knowledge are, in turn, directly related to actual vaccine acceptance.
Clinicians were a major source of information about the HPV vaccine, and participants who reported a clinician as a source of information had more positive perceptions and beliefs about HPV vaccines. Other studies have demonstrated similar findings: in one study, high school girls valued HPV vaccine information from nurses and physicians and receiving information from these clinicians was associated with being vaccinated. 35 Physician recommendation and normative beliefs have been shown to be predictors of HPV vaccination in a number of other studies. 4 Thus, encounters with clinicians should be used to fill vaccine knowledge gaps and open a dialogue about the HPV vaccine with patients and parents. 35 To fill the vaccine knowledge gap and open a dialogue with parents, clinicians should counsel both adolescents and parents about the vaccine’s side effects and safety, cite data on HPV-related cancers, explain how HPV is transmitted, and direct patients and parents as to where they can obtain additional information. 34 However, clinicians may not be providing strong, consistent recommendations for adolescents to receive the HPV vaccine, leading to missed clinical opportunities to vaccinate adolescents against HPV. 36 A more recently published National Survey of Pediatricians and Family Physicians reported that more than 40% do not strongly recommend the vaccine to 11- to 12-year-old girls and nearly 50% do not strongly recommend it for males aged 11 to 12 years. 37 Public health efforts need to focus on creating interventions to assist and support clinicians to effectively communicate information about HPV and the vaccine and implement strong and consistent recommendations for all adolescent vaccines. 38 In addition, these interventions must address factors contributing to providers’ hesitancy to recommend and provide information about the vaccine (eg, lack of knowledge about HPV, discomfort discussing a sexual health topic, and concerns about parental resistance).36,39-44
Only 38% of the participants endorsed their mother as a source of information. This may imply that there is limited communication about the vaccine because of maternal lack of knowledge and understanding, 45 concerns that discussing the vaccine raises issues about sex, 46 discomfort with this subject matter, and/or parents feeling that communication is not warranted because the decision to vaccinate is made by the mother in the interest of her daughter. The literature has supported parent-child communication as a protective factor against high-risk behaviors, including the initiation of vaginal intercourse. 47 However, because there are potential for differences between various racial groups in trusting health care systems, as well as parenting and communication strategies, there is a need for understanding different approaches to address these cultural variations in practice. 45 Despite encouragement to use the HPV vaccine as a teachable moment to talk about reproductive health, 48 only 53% of mothers with daughters aged 9 to 15 years expressed some willingness to talk to their daughters about sex in the context of HPV vaccination. 49 Nonetheless, when the participant’s mother was endorsed as a source of information in our study, the information was reported to be useful, and adolescents reported more positive normative beliefs about the vaccine and less concern about its safety.
Not surprisingly, other individuals, such as father, teacher, friend, and church/synagogue/mosque, were reported less frequently to be sources of information about the vaccine. Adolescents who reported their father as a source of information had lower HPV and HPV vaccine knowledge and were less likely to perceive benefits from the vaccine. This may reflect a different quality of conversation about HPV vaccines between adolescent girls and their fathers, or there may be something different in terms of family structure or dynamics (eg, father is a single parent) that was reflected in our findings. Our findings suggest that, because mothers can clearly be a valuable and influential source of information (and fathers may lack information) about the vaccine, clinicians should provide HPV and HPV vaccine education to both the adolescent and his/her parent.
Several limitations should be acknowledged with regard to this study. First, this study is cross-sectional, and therefore, the association between sources of information and knowledge and vaccine perceptions may not be causal. Additionally, all girls in this study were vaccinated; this study does not address the relationship between sources of information and knowledge or perceptions among unvaccinated adolescent women. However, research documents that women who are vaccinated, compared with unvaccinated women, score higher on HPV and vaccine knowledge questions, implying that unvaccinated women may not have researched their choice, and lacked information to make a decision in either direction. 35 Thus, it is important to determine which sources of information vaccinated women consider important in learning about the HPV vaccine to help develop interventions to provide accurate information and increase knowledge in unvaccinated women.
Conclusion
In summary, this study demonstrates that sources of information about HPV vaccines, including media and individuals, are associated with greater knowledge and more positive perceptions among adolescent girls who received the first HPV vaccine dose. The findings from this study should be used to create culturally appropriate HPV vaccine interventions by disseminating medically accurate information through the most common reported sources of information. Professionals developing interventions should consider the sources of information that were associated with higher knowledge and perceptions, and utilize these avenues to increase adolescents’ HPV vaccine knowledge, improve the appropriateness of their perceptions, and increase vaccine uptake. Furthermore, to maximize the impact of future vaccine campaigns, these findings suggest the need to assess the accuracy of HPV vaccine messages and to heightened awareness of those involved in health care to provide accurate HPV vaccine messages given the associations between media and individuals as sources of information and adolescents’ knowledge and perceptions about the HPV vaccine.
Footnotes
Author Contributions
BLR: Contributed to interpretation; drafted manuscript; critically revised manuscript; gave final approval; agrees to be accountable for all aspects of work ensuring integrity and accuracy.
MLS: Contributed to interpretation; drafted manuscript; critically revised manuscript; gave final approval; agrees to be accountable for all aspects of work ensuring integrity and accuracy.
GDZ: Contributed to conception and design; critically revised manuscript; gave final approval; agrees to be accountable for all aspects of work ensuring integrity and accuracy.
LD: Contributed to acquisition, analysis, and interpretation; critically revised manuscript; gave final approval; agrees to be accountable for all aspects of work ensuring integrity and accuracy.
TLKM: Contributed to interpretation; drafted manuscript; critically revised manuscript; gave final approval; agrees to be accountable for all aspects of work ensuring integrity and accuracy.
JAK: Contributed to conception and design; contributed to acquisition, analysis, and interpretation; critically revised manuscript; gave final approval; agrees to be accountable for all aspects of work ensuring integrity and accuracy.
Declaration of Conflicting Interests
The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr. Kahn served as the chair of a grant review committee for a grant program sponsored by the Society for Adolescent Health and Medicine, which provided funding for public health demonstration projects to improve adolescent vaccination. Funding for the grant program was provided by Merck. Dr. Kahn has also served as cochair of two clinical trials of an HPV vaccine in HIV-infected individuals; these studies were funded primarily by the National Institutes of Health, but Merck provided vaccines and immunogenicity testing. Dr. Zimet has received funding for investigator-initiated HPV-related research from Merck and from Roche Diagnostics. Dr. Shew has and is currently participating as an investigator for Merck and Co, Inc, related HPV vaccine trials. She has received salary support for her efforts.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Institutes of Health (NIAID) R01 073013 (Kahn, PI); National Institutes of Health (NIAID) R01 104709 (Kahn, PI); and the National Institutes of Health (NICHD) K23 072807 (Mullins, PI).