Human papillomavirus (HPV), the most common sexually transmitted virus in the United States,1 remains a considerable public health problem. HPV has been well documented as the virus that causes cervical cancer and genital warts among females.1 More recently, research has identified HPV infections in males and its association with penile and anal cancers,2–4 and with oropharyngeal cancers among individuals with Types 16 and 18 present in oral mucosa.5–9
In 2006, the Food and Drug Administration (FDA) approved a prophylactic quadrivalent HPV vaccine for females (9–26 years), which has demonstrated 100% effectiveness in protecting against HPV types that cause 70% of cervical cancers (Types 16 and 18) and 90% of genital warts (Types 6 and 11).10,11 On October 21, 2009, the Committee on Immunization Practices (ACIP) voted on updated recommendations for use of the HPV vaccine, including a permissive approval of the quadrivalent HPV vaccine for males (9–26 years) to reduce their likelihood of acquiring genital warts.12 Among males, on-going vaccine trials have found the quadrivalent vaccine efficacious in reducing >90% of external genital lesions and ∼90% efficacious in preventing persistent infections caused by the HPV types covered in the vaccine.13
Existing literature suggests that US vaccination efforts, like those of Mexico and Australia, should extend to males to assist in preventing HPV transmission among both sexes.2 Limited research in the United States has examined attitudes and other factors related to males' intention to receive the HPV vaccine; therefore, factors contributing to intent to vaccinate are not well understood. Studies suggest that between 33% and 78% of adult males intend to vaccinate against HPV,14–19 with college samples more likely than non–college samples to report intentions to vaccinate.
Factors affecting vaccination intentions among college students include: ever had sex, had more than 5 sex partners, and had a previous sexually transmitted diseases infection.17,18 Other studies with similar samples including non–college samples also found that vaccine acceptance was higher among males who had recommendations from their parents, partners, and doctors, as well as peers.15–17,19 Concerns about the safety of the vaccine and vaccine costs were also found to be related to whether they would receive the HPV vaccine.15,16,19 Cost was also a factor in vaccine acceptance for a sample of men who have sex with men in Australia.20 This study which examined attitudes of men who have sex with men toward the HPV vaccine found that 47% of the participants were willing to pay $450AUD for the HPV vaccine and 93% were willing to disclose their sexuality to obtain the vaccine for free.20
Studies have been conducted examining parental acceptance of the HPV vaccine.21–24 One study conducted with parents from Canada found that although parents were supportive of a school-based HPV vaccine program, parents reported lower intentions to vaccinate their sons with the HPV vaccine compared to females.24 Parents were more willing to vaccinate their sons if there was more clarity on the clinical benefits of vaccinating their sons, including prevention of genital warts and HPV-related cancers.24 The purpose of the current investigation was to identify factors associated with HPV vaccination intention among males. Data from 2 different samples are presented. The first sample is from the Natural History of HPV Infection in Men: The HIM Study,25 and its behavioral arm, Cognitive and Emotional Responses to HPV in Men (CER). Men from this sample have had considerable exposure to HPV-related information through study involvement.26 For comparison purposes, data are also reported from a separate survey conducted with University males who were not enrolled in HIM or CER, and who were likely “unexposed” to intense HPV messages and testing. This sample of college men was recruited initially when the study investigators first realized that the HPV knowledge scores among CER participants were higher than those in previous studies of HPV knowledge among men. A small comparison study was designed to assess knowledge among “unexposed” men, to report differences in the 2 groups. Vaccine intentions were also added to the comparison survey, but because this was a post hoc decision, the measures/questions do differ between the 2 samples.
MATERIALS AND METHODS
Procedures and study instruments varied considerably between the HPV study sample and the University sample; therefore, procedures for each study are described separately below.
HPV Study Procedures
The study and questionnaire were approved by the Institutional Review Board of the lead author's institution before study initiation. Beginning in March of 2007, a convenience sample of males aged between 18 and 70 years was recruited for HIM.25 Men were recruited from universities (students, faculty, and staff), and the general population using strategies including face to face recruitment in classrooms, publicity at mass events, advertisements targeted to men using radio, television, newspaper ads, direct mailing and word of mouth, and peer leaders of groups with predominated male membership to explain the importance of the study for future efforts to prevent HPV-associated cancers in men and women.
Eligibility requirements for HIM included the following: (1) residency in central Florida; (2) fluency in English; (3) no prior diagnosis of penile or anal cancer, genital warts, or HIV/AIDS; (4) no current symptoms of an sexually transmitted infection (STI); (5) no prior participation in an HPV vaccination study; (6) not homeless, imprisoned or in a drug rehabilitation program in the last 6 months; (7) willingness to comply with scheduled visits every 6 months for 4 years; and (8) no plans to move within the next 4 years. In the HIM study, males are tested for HPV for a total of 10 clinical visits scheduled every 6 months over a period of 4 years. Participants are told their HPV test results from the previous visit at each 6-month visit and it is explained that such results are not FDA-approved for men but are for research purposes only. The nurse practitioner who sees each participant in the HIM study provides general information about HPV on entry into the study, and at each 6-month visit. The HPV information that is shared with participants includes oral and written material, which explain that HPV is a virus, is sexually transmitted, and is associated with certain cancers, and with genital warts. By the time participants in the CER study fill out the survey the first time, they have had educational messages about HPV at the time of enrollment, through the Informed Consent process, and at 3 separate visits with the nurse practitioner.
After receiving their HPV test results the first time, all participants in HIM are then invited to participate in CER, with the primary aim of assessing psychosocial responses to HPV testing during 4 surveys over a 2-year period. Participants are remunerated with $130 over the course of 4 visits for their CER participation. Most who elected not to participate in CER reported that they did not want to attend additional study visits and cited traveling substantial distances as a barrier to attendance. Of the 390 enrolled, 60 failed to return to complete the first visit for CER. Several of those enrolled had not completed the survey at the time of analysis, leaving 302 (70% of the total number eligible) completed surveys.
Every willing participant completed written informed consent. At each visit, participants completed a 168-item computer-assisted self-interview questionnaire at a private computer workstation at the HIM/CER study location, a local cancer center; the questionnaire took about 30 minutes to complete. Instrument items included assessment of psychosocial functioning, sexual behavior, sexual partnership status, information-seeking behavior, and HPV vaccine intentions. Data for this investigation were derived from the first visit of CER, and were collected between March 2007 and January 2009.
HPV Study Instrumentation.
Intent to vaccinate was the dependent variable and was assessed with a single question: “If there was a safe vaccine that could prevent HPV in males, how likely is it that you would be vaccinated?” Participants were asked to respond on a 4 point Likert-type scale, ranging from Very Unlikely (1) to Very Likely (4). Intent scores were later dichotomized for analyses (“Likely” and “Very Likely” were combined and compared to “Unlikely” and “Very Unlikely.” Five categories of independent variable were assessed: individual characteristics, HPV knowledge, motivators for HPV vaccination, perceived barriers to HPV vaccination, and importance of healthcare provider recommendation to be vaccinated. Individual characteristics include demographic information and STI history. HPV knowledge was measured by 20 yes/no items, such as “Most HPV infections clear up within a short time,” “You can transmit HPV even if you do not see a wart,” “HPV can be passed to a newborn at birth,” “HPV is a bacterial infection,” and “Antibiotics can cure HPV.” After correct items were coded as 1 and incorrect items coded as 0, a knowledge score was created by summing the 20 items (theoretical range, 0–20). Motivators for HPV vaccination were assessed with 2 items focused on genital warts, the most common manifestation of HPV in men: “I am concerned that I will get genital warts”; and “I believe that genital warts would be a serious threat to my health”; both were answered on a 6-point Likert-type scale ranging from strongly agree to strongly disagree. Although the association between HPV and anogenital and oral cancers that can affect males as well as females has become a matter of concern (and has been added to the CER study survey under “perceived threat”), we did not include questions about perceived threat of cancer for males in either of these samples. Perceived barriers to HPV vaccination were measured by the question, “If there was a safe and effective vaccine available for men, what do you think would prevent or stop you from being vaccinated against HPV?” Participants were given a list of 9 possible barriers (plus “other” and “nothing”) and asked to mark “all that apply” (Table 1). Lastly, importance of healthcare provider recommendation was assessed by the question, “How important would it be to you that your health care provider (nurse, doctor, counselor, etc.) tell you to be vaccinated against HPV?” with response options of “Very important,” “Somewhat important,” and “Not important at all.” Detailed measurement information for the entire survey, including evidence of reliability and validity, is reported elsewhere.26
University Study Procedures
A convenience sample was recruited from among undergraduate students attending a Public University in Florida. The study and questionnaire were approved by the Institutional Review Board. Before survey administration, instructors (N = 6) for the Introduction to Anthropology courses were e-mailed and asked permission to survey students during class; 100% of the instructors granted researchers permission to visit their class. Questionnaires in paper-and-pencil format were distributed in classrooms. A cover letter explaining the study purpose and advising respondents that completion of the survey constituted informed consent was included with each questionnaire. All students were present in the class that they were invited to participate. Questionnaires were completed in the classroom and, after all surveys were collected, graduate assistants provided students with information and distributed resources about HPV. University males (N = 203) and females (N = 276) were enrolled in the study, but for comparison purposes only data from male participants are reported here.
University Sample Instrumentation.
The dependent variable, willingness to consider HPV vaccination, was assessed with a single categorical question: “Do you intend to receive the HPV vaccine in the future?” Of the 4 response options, those who reported “Yes,” “If I knew more about it” or “I'm not sure” were compared to those who reported “No” as reflecting willingness to consider vaccination; “No” was coded as unwillingness to consider vaccination. As in the CER sample, 5 categories of independent variable were assessed. Individual characteristics include demographic information and STI history. HPV knowledge was assessed with a 23-item questionnaire similar to that used with the CER sample. Motivators for HPV vaccination were assessed with 2 items answered as “Yes” or “No”: “I do not believe the vaccine will work”; and “I am not at risk for HPV.” Perceived barriers to HPV vaccination were assessed with a “check all that apply” list of potential barriers. Respondents were considered to have answered “Yes” if they checked the box corresponding to each barrier and “No” if the box was left blank. Importance of healthcare provider recommendation for vaccination was assessed as in the CER sample.
SPSS Statistics 17.0 was used to conduct all analyses. Descriptive statistics were tabulated for all variables and scale scores were created for HPV knowledge. Bivariate logistic regression analyses were conducted separately for each sample to assess factors associated with men's receptiveness to HPV vaccinations. Variables significantly associated with intent/willingness to vaccinate (either P < 0.05 for trend or confidence interval that does not include the value of “1”) were then entered into a multivariate logistic regression for each sample. Continuous variables were entered into multivariate analyses only if the P value for the trend analysis was significant. However, continuous variables were also dichotomized and presented as such to ease interpretation.
HPV Study Sample Demographic Characteristics
Of the 302 participants who completed the survey, a total of 296 CER participants (M age of 27.8 years; SD = 12.1 year) were included in these analyses as 6 participants declined to answer the intent to vaccinate item (Table 1). Most respondents were white (68.6%), although 17.6% and 15.2% reported being Hispanic and black, respectively. Almost three-quarters were unmarried (74.2%), and most reported having at least some college credit (87.2%). Approximately one-quarter reported having no health insurance at all.
HPV Study Vaccination Intentions and Related Factors
Most respondents reported intent to vaccinate themselves; 93.6% of males noted that it was either likely (30.8%) or very likely (60.9%) that they would be vaccinated if there was a safe and effective vaccine for males. Almost two-thirds (60.8%) reported that a recommendation for HPV vaccination from their health care provider would be very important in their vaccination decision-making. More than half of respondents (59.5% and 58.1%, respectively) reported that a high cost and side effects of a vaccine would prevent or stop them from being vaccinated against HPV. It is noteworthy that respondents' level of HPV-related knowledge was generally high, as measured on a 20-item scale (M = 15 correct, SD = 3).
In bivariate logistic regression analyses, Hispanic men were less likely than non-Hispanic men to intend to vaccinate. In trend analyses, men who had greater concerns about getting genital warts and stronger beliefs that getting genital warts would seriously threaten their health had increased likelihood of intending to vaccinate. Concerns about being able to get an appointment for vaccination and getting time off for vaccination, as well as identifying other barriers to vaccination all were associated with lower likelihood of intending to vaccinate, and were the only variables that independently contributed to intent to vaccinate in the multivariate model (Table 1).
University Sample Demographic Characteristics
A total of 198 male University participants were included in these analyses.
Most respondents were white (71.7%), although 18.8% and 8.4% reported being Hispanic and black, respectively. Most were unmarried and single (91.9%). Approximately one-quarter reported having no health insurance at all.
University Sample Willingness to Consider Vaccination and Related Factors
Few University males (4.6%) reported intent to get vaccinated against HPV in the future; 24.2% marked “If I knew more about it” and 33.3% marked “I'm not sure”; these 3 responses were collapsed to indicate openness to HPV vaccination. Almost 2 of every 5 males (37.9%) reported “No” they did not intend to get vaccinated against HPV. One-fifth reported that they were “not at risk for HPV.” Less than half of University males (44.9%) reported feeling it would be “very important” whether their health care provider made the recommendation to be vaccinated against HPV; 18.4% reported that a health care provider recommendation would be “not important at all.” Few were concerned about the high cost of a vaccine (7.8%). Knowledge about HPV was moderate and widely variable (M = 10.9 correct of 23 items; SD = 6.3; range, 0–21).
In bivariate logistic regression analyses, none of the demographic characteristics were associated with willingness to consider HPV vaccination. Men who had heard of the HPV vaccine, men with higher knowledge scores (P for trend <0.05), and men who thought they “were not at risk for HPV” were less likely to report willingness to consider vaccination. Compared to men who thought healthcare provider vaccination recommendations were “not important at all,” men who thought that it would be “somewhat” or “very important” that their healthcare provider recommended vaccination were more likely to report willingness to consider vaccination. In the multivariate model, having never heard of the vaccine, perceptions of being at risk for HPV, and rating healthcare provider recommendations as important in their vaccine decision-making independently contributed to willingness to consider vaccination (Table 2).
This investigation was uniquely poised to examine vaccine intentions among 2 different groups of males: a sample of adult men who had extensive exposure to information about HPV and HPV vaccination among males, and a sample of University men who had little exposure to information about HPV or vaccination among males. Receptiveness to HPV vaccination varied substantially between the 2 groups: 94% of males who had significant exposure to HPV-related information through a clinical study intended to vaccinate against HPV whether a safe and effective vaccine was available, compared to 62% of University males who were willing to consider HPV vaccination. As expected, most males in the University sample had not even heard of an HPV vaccine—even a vaccine for women. Currently, through pharmaceutical companies' advertisements, the general public has been exposed to messages regarding the importance of HPV vaccination for young women, but men may disregard those messages because they do not pertain directly to them. Little information has been widely circulated regarding HPV and HPV vaccination among males—even in the wake of the recent CDC approval of the HPV vaccine for males 9 to 26 for prevention of genital warts. In the absence of information about HPV vaccination, and specifically information about HPV and HPV vaccination among males, males may be skeptical of receiving HPV vaccination. In fact, men in our University sample who had higher HPV-related knowledge and had heard of the HPV vaccine (vs. not) were less likely to be willing to consider HPV vaccination. Men who have only heard of HPV and HPV vaccination pertaining to women may fail to see the relevance of HPV vaccination to themselves. However, our CER sample shows that after repeated exposure to medically accurate information about HPV among males and females, including information emphasizing the high prevalence of HPV infection among males and the potential benefits of HPV vaccination for their health, most males report intent to vaccinate against HPV when the vaccine becomes available. Thus, these results suggest a tremendous potential for educational/awareness campaigns to successfully promote HPV vaccination for males.
Whereas public service announcements and other media campaigns are important and may be effective, these findings suggest that healthcare providers will have a critical role in promoting HPV vaccination among males. In both samples, most males thought a healthcare providers' recommendation would be important in their decision about HPV vaccination. Other research has demonstrated the important role that providers play in patients' healthcare decisions.18,19 Unfortunately, many young males who would be eligible for HPV vaccination may have few interactions with healthcare providers,27 and thus few opportunities to receive such recommendations. Thus, now that HPV vaccination has received permissive approval for young males, healthcare providers must take advantage of every encounter to inform young males about the vaccine. Such discussions should be sure to address perceived susceptibility to HPV, as University men in this investigation who believed they were not at risk for HPV were significantly less likely to be willing to consider vaccination.
Several critical windows of opportunity for HPV-related education exist and should be maximized, including: (a) sports-related and camp-related physicals; (b) medical visits for sports-related injuries; and (c) precollege physicals, which are required for all males who are college bound. Outreach workers or community-based patient navigators28,29 may also be used to create linkages between males and healthcare providers as well as to provide males with information regarding the HPV vaccine. Popular opinion leader interventions may also be successful at encouraging vaccination among men.30,31Additionally, friends, families, and partners may play a significant role in reaching out to men about the HPV vaccine and encouraging them to do their part to protect their families and loved ones.
Reducing perceived barriers to vaccination may be important for ensuring that men who desire vaccination actually receive the vaccine. Recent studies found that several barriers, such as cost, hassle of receiving a 3-shot series, safety, and side effects were associated with vaccine acceptability in males.15–19 In our sample of men enrolled in a longitudinal study of HPV infection, these barriers were not significantly associated with intent to vaccinate. However, more than half of the men who had been exposed to extensive information about HPV and HPV vaccination and who intended to vaccinate still expressed concerns about the potential high cost of vaccination as well as possible side effects. Other studies have demonstrated discordance between intention and behavior, and barriers such as high costs or potential side effects could prevent men who intend to get vaccinated from actually receiving the vaccine. Future research should explore whether concerns about costs and side effects moderate the relationship between intent to vaccinate and vaccination behavior. Moreover, “other” barrier remained significant and requires further exploration. Whereas “other” barrier does not specifically identify which barrier(s) to target in future interventions, the response does suggest that participants in the study who had additional concerns about vaccination (those not provided in the existing barrier list) are less likely to vaccinate. This finding indicates that more formative work may be needed to more fully understand the factors that may prevent men from receiving vaccination.
Results of these studies should be interpreted in light of several limitations. Data for the CER study were collected as part of a natural history study of HPV in males, and those enrolled in the study may differ in some ways from the overall population of the community from which they were drawn. For example, enrolled males were relatively young (M = 28 years). Males enrolled in a study of HPV may also differ from the broader community in their willingness to discuss and be examined for STIs. University males were recruited from a single university and are not representative of the broader community, or of all University males throughout the United States. In addition, the small number of University males who reported intent to vaccinate (N = 8, 4.5%) precluded an analysis focusing on whether these men intended to vaccinate, and instead necessitated exploration of men's willingness to consider vaccination. Finally, a small comparison study was designed to assess knowledge among “unexposed” men, in order to report differences in the 2 groups. Motivations regarding HPV vaccination were assessed with 1 item assessing susceptibility and 1 item assessing severity of genital warts. Vaccine intentions were also added to the comparison survey (University sample), but because this was a post hoc decision, the measures/questions do differ between the 2 samples. Single item measures are less ideal than assessment with multiple items. Additionally, genital warts are not the only potential manifestations of HPV—recent research has linked HPV among men to penile, anal, and oropharyngeal cancers,2–9 and concerns about such cancers should be studied in relation to HPV vaccination among men. Subsequently, these items have been added to the CER instrument, and will be reported at a later date. Nevertheless, findings from the current study are important. This is the first known study to suggest that when exposed to substantial information about HPV, a substantial proportion of males may be willing to vaccinate against HPV. Moreover, this study adds to the literature by identifying factors that may account for differences in HPV vaccine intentions.
In conclusion, the current study suggests that repeated exposure to information about HPV more generally and about HPV vaccination in males more specifically may result in high rates of vaccination among men. Moreover, men value the recommendations of healthcare providers, and thus, healthcare providers should be part of HPV vaccination promotion activities that target males. Data from our University sample suggest there is a substantial need for educational campaigns to disseminate knowledge about HPV among men. Recent studies on the relationship between HPV and oral, penile, and anal cancers suggest that the personal consequences of HPV infection for men may be more significant than previously thought.2 Other studies suggest that the quadrivalent HPV vaccine may be effective in preventing oral, penile, and anal cancers.32 These scientific advances may substantially change the way we educate men about HPV vaccination. It will be important to understand how men's changing knowledge about the relationship between HPV and male cancers affects their willingness to receive HPV vaccination themselves and to encourage the women in their lives to be vaccinated as well.
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