by Stephanie E. Wever June 2012

Transcription

1 Psychosocial factors influencing HPV vaccine uptake among female adolescents in Philadelphia, PA by Stephanie E. Wever June 2012 A Community Based Master s Project presented to the faculty of Drexel University School of Public Health in partial fulfillment of the Requirement of the Degree of Master of Public Health

2 ii ACKNOWLEGDEMENTS I would like to thank my parents: Debbie Wever, Michael Wever and Donna Duffy for their support and encouragement. I would also like to thank my siblings: Vanessa, Thomas and Matthew, for reminding me to take a break and play. Additionally, I would like to thank Lucy Pleticha for her support and reassurance. I would also like to thank my advisor Dr. Yvonne Michael and my community preceptor Dr. Amy Leader for giving me the opportunity and guidance throughout this project.

3 iii LIST OF TABLES Table 1. Psychosocial Measures of independent variables..8 Table 2. Knowledge about HPV virus...11 Table 3. Knowledge about HPV vaccination.11 Table 4. Knowledge of HPV virus by age group...12 Table 5. Knowledge of HPV vaccine by age group...12 Table 6. Communication beliefs 13 Table 7. Communication beliefs by age group..13 Table 8. Self-Efficacy beliefs 14 Table 9. Self-Efficacy beliefs by age group..14 Table 10. Association of Psychosocial factors with high intention to vaccinate...16 Table 11. Association of Psychosocial factors with receipt of first vaccination...18 Table 12. Association of Psychosocial factors with receiving both the first and second HPV vaccination.19

4 iv LIST OF FIGURES Figure 1. Applying TPB constructs to HPV vaccination 3

5 v ABSTRACT Psychosocial factors influencing HPV vaccine uptake among female adolescents in Philadelphia, PA Stephanie E. Wever 1 Dr. Yvonne Michael 1 and Dr. Amy Leader 2 1 Drexel University School of Public Health 2 Thomas Jefferson University Objective: To determine how psychosocial factors, including knowledge, self-efficacy, and communication, predict intention to receive the HPV vaccination and actual vaccination uptake. Methods: A secondary data analysis of African American adolescent females (n=200) aged 12 to 18 years in Philadelphia, PA who participated in an educational intervention program called HPV Vaccination of Underserved Adolescents and Young Women in Pennsylvania. Baseline survey data was used to assess psychosocial factors and intention to receive vaccine. Uptake of HPV vaccination was assessed through linkage to the Philadelphia KIDS immunization registry. Results: In this population of urban adolescents, 44 % had high intention to vaccinate, 36.9% received the first HPV vaccination and 20.7% received both the first and second vaccination out of a three dose series. Self-efficacy and communication with parents and health care providers were associated with intention to vaccinate. Compared to those with low self-efficacy, participants with moderate or high efficacy scores had increased odds of intention to vaccinate (OR=5.01, 95% CI and OR=28.20, 95% , respectively) and those with moderate to high communication scores have an increased odds for intention to vaccinate compared to those with low communication scores (OR= 3.48, 95% and OR=9.62, 95% ). Knowledge of the HPV virus and self-efficacy was significantly associated with receiving the first HPV vaccination, whereas only knowledge of the HPV virus was associated with receipt the first and second vaccination. Intention to receive HPV vaccine was not associated with receipt of vaccine. Conclusions: Future health educational interventions directed towards urban adolescents should focus on increasing participant s self-efficacy to receive the HPV vaccination along with increasing their knowledge of the vaccine itself.

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7 1 1. Introduction In the United States, the Center for Disease Control and Prevention (CDC) estimated that 6.2 million people were infected with Human Papillomavirus (HPV) in 2007 (1). Of the multiple serotypes of the HPV virus worldwide, 70% of all invasive cervical cancers are caused by two variants, 16 and 18, and 90% of all anogenital warts are caused by variants 6 and 11 (2-4). In addition, the HPV virus is the most commonly transmitted sexual infection in the United States; 64% of women aged 13 to 26 are infected with at least one strain of the virus (3). Of those infected with at least one strain of the HPV virus, 54% of women were infected with a high-risk strain that is know to cause either cervical cancer or genital warts (3). The HPV vaccine (HPV4, Gardasil) was designed to prevent infection from HPV types 6, 11, 16 and 18 and reduce incidence of cervical cancer and anogenital warts (5). In 2007, the CDC s Advisory Committee on Immunization Practices recommended that adolescents females start the HPV vaccination series between the ages of 11 and 12 (1). Additionally, females up the age of 26 that have not been sexually active should be vaccinated (1). The quadrivalent HPV vaccination is a 3 dose vaccine with the 2 nd and 3 rd doses given at 2 and 6 months after the initial vaccination (1). In the United States, disparities in rates of cervical cancer exist by race and socioeconomic status. Women of racial minorities and lower socioeconomic status have the highest rates of cervical cancer (4, 6). African American women are 1.5 times more likely to be diagnosed with cervical cancer than non-hispanic white women. African American women are also two times more likely to die from cervical cancer than white women. Rates of HPV infection are also unequally distributed among racial minorities, with African Americans more likely than their White counterparts to be diagnosed with a high-risk HPV strain

8 2 (OR=2.54, ) (3). In addition, African American women are twice as likely than their White counterparts to be infected with a strain of the virus that can be prevented from the vaccine (OR=1.90, ) (3). The use of the HPV vaccination, along with Papanicolaou (Pap) smears, are necessary to prevent cervical cancer and HPV infection (6). Studies have shown that vaccinations are 99.9% effective in preventing HPV infection, if given at the appropriate dosage and on the correct timetable (5-7). Given the higher rates of high risk HPV infection in African American women, the HPV vaccination will reduce the disparity of HPV infection if vaccination is target toward high-risk populations. However, even though there is a significant protective effect of the HPV vaccine, there has been a low uptake of the vaccination. The 2010 CDC rates show that only 48.7% of females aged 13 to 17 started the vaccination series (8). These estimates are consistent with the 2008 National Immunization Survey Teen (9). There is a need for research to explain barriers to the initial uptake of the vaccination but also compliance with the vaccination series, specifically focusing on populations that are at greatest risk of cervical cancer. Prior studies have shown that African American adolescents are less likely initiate the vaccination or complete the vaccination series (10, 11). Additionally, those with public health insurance are less likely to complete the vaccination series than those who have private insurance (OR = 0.69, ) (11). Age is another significant factor in HPV vaccine uptake; adolescents females aged are 16% more likely to initiate the HPV vaccine and are 16% more likely to complete the vaccination series (10). Furthermore, socioeconomic status has been shown to influence HPV vaccine uptake. Adolescents living below the federal poverty level are 24% less likely to initiate the vaccine series (12). These studies have

9 3 primarily focused on race/ethnicity, age, access to healthcare, and socioeconomic status as factors associated with HPV vaccination uptake and completion or parental attitudes towards vaccination (10-17). This current study seeks to understand the psychosocial factors that influence vaccination intention and uptake in a subset of low-income, urban, minority adolescents in Philadelphia, PA. The Theory of Planned Behavior (TPB) guided the development of the educational intervention HPV Vaccination of Underserved Adolescents and Young Women in Pennsylvania and similarly guided the psychosocial constructs used in this study. The TPB states that an individual s intention to perform a behavior, in this case receiving the HPV vaccination, is based on their attitude towards the behavior, subjective norm, and their perceived behavioral control (18, 19). Subjective norm and perceived behavioral control were assessed using proxies for self-efficacy and communication. Knowledge lies outside of the TPB (Figure 1). Figure 1. Applying TPB constructs to HPV vaccination Attitudes Knowledge Subjective Norm Communication Intention to vaccinate Vaccination Perceived Behavioral Control Self-Efficacy Directly Assessed in Analysis

10 4 An individual s perceived control is determined by control beliefs concerning the presences or absence of facilitators and barriers to behavior performance. Our self-efficacy index score measured the participants ability to receive the vaccination though their selfassessment of having enough knowledge to receive HPV and their perceived ability to communicate with healthcare providers and parents (Table 1) (19). Subjective norm is determined by [a person s] normative beliefs whether important referent individuals approve or disapprove of performing the behavior. Our communication index score is a proxy capturing the individual s self-reported ability to communicate the need to vaccinate with healthcare workers and parents, two important stakeholders in adolescents lives (19). A recent study of females over the age of 18 showed that a mother s approval of vaccination was positively associated with vaccine uptake (OR % CI ) (20). By separating each construct in our analysis, we can understand how each influences the intention to vaccinate and ultimately, the uptake of the vaccination itself. Previous studies have shown that knowledge, efficacy, and normative beliefs are factors that are positively associated with intention (21). Additionally, TPB asserts that intention is a direct determinate of a behavior, in this instance, to receive the HPV vaccination (19). Therefore, by assessing the TPB constructs in relation to intention and then to behavior, we will be able to better describe psychosocial factors that influence HPV vaccination. These psychosocial factors, unlike race, social-economic status and insurance status can be modifiable though educational interventions. Understanding how these psychosocial factors influence HPV vaccination, we can better inform future interventions.

11 5 2. Specific Aims The specific aims of this study are: -To estimate the association between adolescent s knowledge, efficacy, and communication with parents and health care providers related to HPV vaccine and their intention to start the HPV vaccination series -To estimate the association between adolescent s knowledge, efficacy, and communication with parents and health care providers related to HPV vaccine and uptake of the HPV vaccination as reported from the Philadelphia KIDS vaccination registry. 3. Research Design and Methods Overview We will conduct a longitudinal study (n=200) of adolescent females aged from Philadelphia, PA who were members of the control group from an educational intervention study HPV Vaccination of Underserved Adolescents and Young Women in Pennsylvania. Using the survey data collected at baseline from the participants, we will estimate the association between knowledge, efficacy, and communication with parents and health care providers and intention to receive HPV vaccination. Through linkage with the Philadelphia KIDS registry we will assesse the association between knowledge, efficacy, communication with parents and health care providers and intention with the receipt of the HPV vaccination.

12 6 Participants The participants recruited to participate as members of the control group for the educational intervention study HPV Vaccination of Underserved Adolescents and Young Women in Pennsylvania. Participants had to between the ages of years, had not started the HPV vaccination series, not currently pregnant or breastfeeding and had a successfully match in the Philadelphia Department of Health s KIDS registry. Study Variables and Methods of Data Collection Independent Variables Psychosocial factors were operationalized from the baseline survey. Age at baseline was calculated as a continuous variable from date of birth and date the survey was administered. The knowledge factors were separated into two variables: knowledge of the HPV virus and knowledge of the HPV vaccine itself. Seven specific survey items assessed knowledge of the HPV virus and nine specific items assessed knowledge of the HPV vaccine having nine survey items (Table 1). The Cronbach s alpha coefficient for internal reliability for the knowledge factors was moderate to poor with knowledge of the vaccine scoring α = 0.70 and knowledge of the virus scoring α = 0.65, respectively (Table 1). A 1 was assigned if the respondent answered the survey item correctly and a 0 if the survey question was answered incorrectly or if they responded with I don t know. The knowledge variable for both knowledge of the HPV virus and vaccination are index score calculated by taking the mean of all appropriate survey items with missing values not included in the calculations with higher scores indicating greater knowledge (Table 1). Missing data was less then 1.5 % of the total participants for any knowledge survey item.

13 7 The communication and self-efficacy scores were assessed using a 5-point Likert items with strongly agree corresponding to a 5, agree corresponding to a 4, agree/disagree corresponding to a 3, disagree corresponding to a 2 and strongly disagree corresponding to a 1. The index score was calculated as the mean of three survey items for communication and four survey items for self-efficacy with missing data not included in the calculation. Missing data was less then 0.5 % of the total participants for any communication or self-efficacy survey item. The Cronbach s alpha coefficient for internal reliability for communication and self-efficacy was acceptable with communication scoring α = 0.83 and self-efficacy scoring α = 0.77 (Table 1). Again, those higher scores indicated greater ability to communicate about their need for the HPV vaccination or more self-efficacy. Additionally, sexual activity was assigned as a binary outcome (yes =1) if the respondent self-reports ever being sexually active. Dependent Variables The dependent variable of intention to vaccinate was assessed from the question I plan to get the HPV shot in the next 3 months on a 5-point Likert scale. Participants responding Strongly Agree or Agree assessed as having high intention to vaccinate. Vaccination was assessed from the Philadelphia KIDS registry in July The KIDS registry houses data on approximately 540,000 individuals and contains documentation on more then 7 million immunizations (22). Participants were followed for a median of 17 months, with a range of 8 to 25 months. Those participants with a date of vaccination after the date of initial survey for the first dose were counted as being vaccinated for the first dose and a similar procedure was used for each of the two remain dosage.

14 8 Table 1. Psychosocial Measures of independent variables Measure Knowledge - HPV Virus Crombach α = 0.65 Knowledge - HPV Vaccine Crombach α = 0.70 Communication Crombach α = 0.82 Efficacy Crombach α = 0.77 Survey item HPV is the most common STD in the U.S.? HPV causes most cases of cervical cancer and genital warts? Everyone who has cervical cancer has HPV? A girl cannot get HPV if there is no penetration during sex? Having sex with more than one person increases a girl s chances of getting HPV? Using a condom during sex lowers the chance of getting HPV? Genital warts caused by HPV are always seen on the outside of the vagina? A girl can tell if her sexual partner has HPV? The HPV shot protects against most cases of cervical cancer? The HPV shot protects against most cases of genital warts? Women will never need Pap tests if they get the HPV shot? The HPV shot is recommended for girls as young as 9 years old? Girls who have never had sex do not need to get the HPV shot? If a girl gets the HPV shot she does not need to use condoms during sex? Some doctors and nurses offer the HPV shot to girls 18 years of age and younger for free? All girls need their parent or guardian s permission to get the HPV shot? All three shots of the HPV shot are needed to fully protect against HPV? I plan to talk to my parent or guardian about HPV and the HPV shot in the next 3 months? I am comfortable talking to my parent or guardian about the HPV shot in the next 3 months? I plan to talk to my doctor or nurse about HPV and the HPV shot in the next 3 months? If I really want to, I can get the HPV shot in the next 3 months? I am able to get the HPV shot in the next 3 months? I know enough about the HPV shot to decide if I want to get it in the next 3 months? I could explain to my parent or doctor why I want to get the HPV shot in the next 3 months? Score range

15 9 IRB Considerations The study was approved for exempt category four from The Office of Regulatory Research Compliance at Drexel University College of Medicine. The study qualified for the exempt status as the survey data has already been collected by the HPV Vaccination of Underserved Adolescents and Young Women in Pennsylvania study and all records where de-identified before we obtained the data. Data Analysis Statistical analysis was performed using SAS 9.2. Normality and distribution of dependent and independent variables were assessed. Knowledge, efficacy, and communication scores were categorized into tertiles. Univariate and multivariate regression analysis was to assess the association between knowledge, communication and self-efficacy with intention to vaccination and the association between knowledge, communication, self-efficacy and intention with uptake of vaccination. The univariate regression analysis modeled each independent variable separately with the dependent variable of interests. Multivariate analysis for intention to vaccinate was modeled adjusting for age and sexual activity for each independent variable (knowledge, communication or self-efficacy). Additionally, there were two multivariate analysis models for vaccination status. The first multivariate model, vaccination status was modeled adjusting for age and sexual activity for each of the independent variables (knowledge, communication, self-efficacy or intention to vaccinate). The second multivariate model, vaccination status was modeled adjusting for age, sexual activity and intention to vaccinate for the following independent variables of knowledge,

16 10 communication and self-efficacy. Regression coefficients where considered significant if p < Results The total sample size was 200 adolescent females in Philadelphia. The participants ranged in age from 12 to 18.5 years old, with a mean age of 15.8 years. Less then half of the participants reported high intention to vaccinate (44%). Uptake of the HPV vaccination was low with only 36.9% starting the HPV vaccination series and 20.7% receiving both the first and second vaccination. All of the questions had less than 50 % of the participants responded correctly to each of the knowledge of the HPV virus questions, with the question Genital warts are caused by HPV are always seen on the outside of the vagina? having the smallest percentage of correct responses (Table 2, Table 3). Many of the participants had low knowledge of the HPV vaccine with less than 50% of the participants responding correctly, expect for the question If a girl gets the HPV shot she does not need to use condoms during sex? (Table 3). Of all participants, those aged had a higher percentage responding correctly than those participants aged (Table 4, Table 5). Again, the question scoring the lowest percentage for knowledge of the HPV vaccine was about genital warts (Table 3).

17 11 Table 2. Knowledge about HPV virus Item n (%) answering correctly Missing, n (%) HPV is the most common STD in the U.S.? 45 (22.5) 1 (0.5) HPV causes most cases of cervical cancer and genital warts? 83 (41.5) 0 Everyone who has cervical cancer has HPV? 72 (36.0) 2 (1.0) A girl cannot get HPV if there is no penetration during sex? 61 (30.5) 4 (2.0) Having sex with more than one person increases a girl s chances of getting HPV? 85 (42.5) 2 (1.0) Using a condom during sex lowers the chance of getting HPV? 85 (42.5) 2 (1.0) Genital warts caused by HPV are always seen on the outside of the vagina? 35 (17.5) 2 (1.0) A girl can tell if her sexual partner has HPV? 94 (47.0) 2 (1.0) Table 3. Knowledge about HPV vaccination n (%) answering correctly Missing n (%) Item The HPV shot protects against most cases of cervical cancer? 87 (43.5) 0 The HPV shot protects against most cases of genital warts? 42 (21.0) 2 (1.0) Women will never need Pap tests if they get the HPV shot? 72 (36.0) 0 The HPV shot is recommended for girls as young as 9 years old? 46 (23.0) 3 (1.5) Girls who have never had sex do not need to get the HPV shot? 92 (46.0) 2 (1.0) If a girl gets the HPV shot she does not need to use condoms during sex? 128 (64.0) 2 (1.0) Some doctors and nurses offer the HPV shot to girls 18 years of age and younger for free? 64 (32.0) 0 All girls need their parent or guardian s permission to get the HPV shot? 47 (23.5) 0 All three shots of the HPV shot are needed to fully protect against HPV? 77 (38.5) 1 (0.5)

18 12 Table 4. Knowledge of HPV virus by age group Item n (%) answering correctly Age Age HPV is the most common STD in the U.S.? 6 (3.5) 34 (19.9) HPV causes most cases of cervical cancer and genital warts? 14 (8.1) 61 (35.5) Everyone who has cervical cancer has HPV? 13 (7.7) 50 (29.4) A girl cannot get HPV if there is no penetration during sex? 9 (5.4) 48 (28.6) Having sex with more than one person increases a girl s chances of getting HPV? 9 (5.4) 62 (36.5) Using a condom during sex lowers the chance of getting HPV? 9 (5.4) 65 (38.2) Genital warts caused by HPV are always seen on the outside of the vagina? 2 (1.2) 29 (12.1) A girl can tell if her sexual partner has HPV? 8 (4.7) 75 (11.12) Table 5. Knowledge of HPV vaccine by age group Item n (%) answering correctly Age Age The HPV shot protects against most cases of cervical cancer? 7 (4.0) 68 (39.5) The HPV shot protects against most cases of genital warts? 3 (1.8) 33 (19.4) Women will never need Pap tests if they get the HPV shot? 12 (7.0) 57 (33.1) The HPV shot is recommended for girls as young as 9 years old? Girls who have never had sex do not need to get the HPV shot? If a girl gets the HPV shot she does not need to use condoms during sex? Some doctors and nurses offer the HPV shot to girls 18 years of age and younger for free? All girls need their parent or guardian s permission to get the HPV shot? All three shots of the HPV shot are needed to fully protect against HPV? 4 (2.4) 33 (19.4) 14 (8.2) 68 (39.5) 9 (5.2) 47 (27.3) 2 (1.2) 39 (22.7) 15 (8.8) 53 (31.0) The majority of participants (59.9%) felt comfortable communicating with their parents about receiving the HPV vaccination in the next three months (Table 6). The majority

19 13 of participants also planned on talking with their parents or health care providers about the HPV vaccination in the next three months, 63.9% for both (Table 6). Again, those aged had higher percentage of participants feeling comfortable communicated with parents or healthcare providers (Table 7). Table 6. Communication beliefs Item Agree, n (%) Missing n (%) I plan to talk to my parent or guardian about HPV and the HPV shot in the next 3 months? 123 (61.5) 3 (1.5) I am comfortable talking to my parent or guardian about the HPV shot in the next 3 months? 128 (64.0) 2 (1.0) I plan to talk to my doctor or nurse about HPV and the HPV shot in the next 3 months? 127 (63.5) 2 (1.0) Table 7. Communication beliefs by age group Item Agree, n (%) Age Age I plan to talk to my parent or guardian about HPV and the HPV shot in the next 3 months? 26 (15.3) 121 (71.2) I am comfortable talking to my parent or guardian about the HPV shot in the next 3 months? 27 (15.9) 121 (71.2) I plan to talk to my doctor or nurse about HPV and the HPV shot in the next 3 months? 24 (14.1) 120 (20.6) To assess the participants self-efficacy for receiving the HPV vaccination, more then 50 % of participants responded that they could get the HPV vaccination in the next 3 month and they were able to get HPV vaccination (Table 8). Additionally, less than 50 % of respondents felt that they knew enough or could communicate why they wanted the vaccine to parents or health care providers (Table 8). Participants aged had a greater percentage responding agree to self-efficacy questions then participants aged (Table 9).

20 14 Table 8. Self-Efficacy beliefs Item Agree (n, %) Missing n (%) If I really want to, I can get the HPV shot in the next 3 months? 124 (62.0) 0 I am able to get the HPV shot in the next 3 months? 104 (52.0) 1 (0.5) I know enough about the HPV shot to decide if I want to get it in the next 3 months? 44 (22.0) 1 (0.5) I could explain to my parent or doctor why I want to get the HPV shot in the next 3 months? 94 (47.0) 1 (0.5) Table 9. Self-Efficacy beliefs by age group Item Agree (n, %) Age Age If I really want to, I can get the HPV shot in the next 3 months? 27 (15.7) 130 (75.6) I am able to get the HPV shot in the next 3 months? 26 (15.1) 129 (75.0) I know enough about the HPV shot to decide if I want to get it in the next 3 months? 13 (7.6) 76 (44.4) I could explain to my parent or doctor why I want to get the HPV shot in the next 3 months? 22 (12.9) 114 (66.7) Psychosocial factors scale index Knowledge of HPV virus and HPV vaccine index score had a range of 0-1. Mean and standard deviation of these index scores were 0.35 (0.26) and 0.37 (0.26), respectively. Communication and self-efficacy index scores had a range of 1-5, with a mean and standard deviation of 3.67 (1.03) and 3.31 (0.83), respectively. Psychosocial factors associated with intention to receive HPV vaccine Of the psychosocial factors assessed, only self-efficacy and communication with parents and healthcare providers was significantly associated with intention to receive the HPV vaccination after controlling for age and sexual activity (Table 10). In comparison with

21 15 those with low self-efficacy, those with moderate or high efficacy scores were more likely to report high intention to vaccinate (OR=5.008, 95% CI and OR=28.194, 95% , respectively) (Table 10). Also, in comparison with those with low communication, those with moderate or high communication scores were more likely to report high intention to vaccinate (OR= 3.483, 95% and OR=9.623, 95% ) (Table 10).

22 16 Table 10. Association of Psychosocial factors with high intention to vaccinate (n=200) Low Intention n (%) High Intention n (%) Unadjusted Odds Ratio (95% CI) Adjusted* Odds Ratio (95% CI) Factors Knowledge of HPV virus low 35 (17.5) 25 (12.5) ref ref moderate 34 (17.0) 33 (16.5) ( ) ( ) high 43 (21.5) 30 (15.0) ( ) ( ) Knowledge of HPV vaccine low 52 (26.0) 29 (14.5) ref ref moderate 30 (15.0) 27 (13.5) ( ) ( ) high 30 (15.0) 32 (16.0) ( ) ( ) Efficacy low 48 (24.0) 6 (3.0) ref ref moderate 47 (23.5) 28 (14.0) ( ) ( ) high 17 (8.5) 54 (27.0) ( ) ( ) Communication low 47 (23.5) 11 (5.5) ref ref moderate 44 (22.0) 33 (16.5) ( ) ( ) high 21 (10.5) 44 (22.0) ( ) ( ) Age ( ) - Sexual Activity ( ) - *controlled for age and sexual activity

23 17 Psychosocial factors associated with HPV vaccination Only knowledge of virus and self-efficacy were significantly associated (Table 11). After controlling for age, sexual activity, and intention to vaccinate, those in the moderate and high knowledge of virus had twice the likelihood of receiving the first vaccination (OR = 2.291, 95% and OR=2.032, 95% ) compared to those with low knowledge. Only knowledge of the virus was significantly associated with receipt of both the first and second vaccination in a three vaccination series (Table 12). After controlling for age, sexual activity and intention to vaccinate, those with moderate knowledge of the HPV virus were three times as likely to receive the second HPV vaccination than those with low knowledge (OR=3.080, 95% ). Intention was not associated with the receipt of the HPV vaccine.

24 Table 11. Association of Psychosocial factors with receipt of first vaccination (n=200) Not Vaccinated, Unadjusted Odds Ratio Factors Vaccinated, n (%) (95% CI) n (%) Adjusted Model 1 Odds Ratio (95% CI) Adjusted Model 2 Odds Ratio (95% CI) Knowledge of HPV virus low 16 (8.0) 44 (22.0) ref ref ref moderate 20 (10.0) 47 (23.5) ( ) ( ) ( ) high 24 (12.0) 49 (24.5) ( ) ( ) ( ) Knowledge of HPV vaccine low 17 (8.5) 64 (32.0) ref ref ref moderate 21 (10.5) 36 (18.0) ( ) ( ) ( ) high 22 (11.0) 40 (20.0) ( ) ( ) ( ) Self-Efficacy low 11 (5.5) 43 (21.5) ref ref ref moderate 23 (11.5) 52 (26.0) ( ) ( ) ( ) high 26 (13.0) 45 (22.5) ( ) ( ) ( ) Communication low 16 (8.0) 42 (21.0) ref ref ref moderate 22 (11.0) 55 (27.5) ( ) ( ) ( ) high 22 (11.2) 43 (21.5) ( ) ( ) ( ) Intention low 30 (15.0) 82 (41.0) ref ref - high 30 (15.0) 58 (29.0) ( ) ( ) - Age ( ) - - Sexual Activity ( ) - - Model 1: Controlled for age and sexual activity Model 2: Controlled for age, sexual activity and intention to vaccinate 18

25 19 Table 12. Association of Psychosocial factors with receiving both the first and second HPV vaccination (n=200) Not Vaccinated, Unadjusted Odds Adjusted Model 1 Factors Vaccinated, n (%) Ratio (95% CI) Odds Ratio (95% CI) n (%) Adjusted Model 2 Odds Ratio (95% CI) Knowledge of HPV virus low 8 (4.0) 52 (26.0) ref ref ref moderate 8 (4.0) 59 (29.5) ( ) ( ) ( ) high 8 (4.0) 65 (32.5) ( ) ( ) ( ) Knowledge of HPV vaccine low 6 (3.0) 75 (37.5) ref ref ref moderate 11 (5.6) 46 (23.0) ( ) ( ) ( ) high 7 (3.6) 55 (27.0) ( ) ( ) ( ) Self-Efficacy low 3 (1.5) 51 (25.5) ref ref ref moderate 10 (5.0) 65 (32.5) ( ) ( ) ( ) Communication high 11 (5.5) 60 (30.0) ( ) ( ) ( ) low 6 (3.0) 52 (26.0) ref ref ref moderate 8 (4.0) 69 (34.5) ( ) ( ) ( ) high 10 (5.0) 55 (27.5) ( ) ( ) ( ) Intention low 11 (5.5) 101 (50.5) ref ref - high 13 (6.5) 75 (37.5) ( ) ( ) - Age ( ) - - Sexual Activity ( ) - - Model 1: Controlled for age and sexual activity Model 2: Controlled for age, sexual activity, and intention to vaccinate

26 20 5. Discussion The HPV virus is a major public health concern in the United States as it is one of the most commonly transmitted sexual infections (3). Therefore, understanding what psychosocial factors lead to intention to receive the HPV vaccination and vaccine uptake is a priority in order to help develop successful health education interventions. Self-efficacy, the participant s belief in and ability to receive the HPV vaccination, and communication with parents and healthcare providers were the only two factors that significantly associated with intention to vaccinate. However, only knowledge of the HPV vaccine and high self-efficacy were significantly associated with vaccine uptake (receiving the first HPV vaccination) after controlling for age, sexual risk, and low intention. Only moderate knowledge of the HPV vaccine was significantly associated with receiving the first and second HPV vaccination. Intention is not significantly associated with vaccination. A previous study by Kahn et al. found that knowledge of the HPV virus was significantly associated with intention to receive the HPV vaccination. However in our study, only efficacy and communication were significantly associated (21). Also, Conroy et al. found no significant difference in self-efficacy in those who received the HPV vaccination or those who intended to get vaccinated and those who did not (21). Our study supports the association of self-efficacy with intention to vaccinate yet does not support the association with vaccination. This conflict is consistent with current findings. Our participants have a lower mean knowledge of the HPV virus than in the pervious 2008 Gerend and Magloir study assessing awareness, knowledge, and beliefs about HPV. However, even though the racial composition of their study was approximately the same as our study, the mean age of their population was much other than our study. Gerend and

27 21 Magloir primarily surveyed college students while this study surveyed adolescents; this could account for differences in data (23). Our mean for knowledge of the HPV virus was also lower than in the 2007 Kahn et al. study but they also were working with an older population (21). Additionally, Kahn et al. found that knowledge of the HPV virus was significantly associated with intention to receive the HPV vaccination but in our study only efficacy and communication were significantly associated (21). Study limitations need to be contemplated when interpreting our findings. One of our limitations was that intention to vaccinate was measured as a cross-sectional study. Additionally, no one in our study completed the HPV three dose vaccine series, with only 36.9% of participants receiving the first dose and 20.7% receiving first and second dose. Also, our study was unable to control for other known confounders such as insurance status and poverty level (10, 12, 13). Selection bias is also a concern when excluding participants who did not have a match in the Philadelphia KIDS immunization registry. Only participants who have had a previous vaccination would have been present in the KIDS immunization registry. Therefore, there could be a significant difference in access to healthcare for those excluded in our study. The main tool for measurement of the psychosocial factors was a self-reported survey. Participants may have felt a need to respond with a more socially-desirable response. This could explain why self-reported intention to vaccinate is not a predictor of actual vaccination. However, the biases would be non-differential and the direction of the biases cannot be predicted. The use of the Theory of Planned Behavior as a framework for our study may have been a poor marker for understanding how intention leads to vaccination. Only the

28 22 psychosocial factors of communication and self-efficacy fit within the TPB framework and the index scores created to measure these factors may have been a poor construct for the true TPB constructs of subjective norm and perceived behavioral control. The study s strengths are that it is one of few studies assessing psychosocial factors of adolescents leading to intention to vaccination and vaccination. Our study focuses on a population of great interest in relation to creating health intervention to decrease health disparities for transmission of HPV virus and cervical cancer rates. Furthermore, our study focuses on factors that can be modifiable, such as knowledge, self-efficacy and ability to communicate with parents and health-care providers. Also, our vaccination status was determined using a city-wide vaccination registry. Future research should focus on the barrier between adolescents intention to vaccinate and vaccination as our study shows that intention dose not lead to vaccination as predicted by the TPB. Additionally, future research should focus on the psychosocial factors leading to the completion of the HPV vaccination series. 6. Conclusions and Recommendations Moderate to high levels of self-efficacy and ability communicate with healthcare workers and parents are associated with increased probability of high intention to receive HPV vaccination. However, knowledge of the HPV vaccine and self-efficacy was significantly associated with receiving the first HPV vaccination and only knowledge of the HPV vaccine was significantly associated with receiving the first and second HPV vaccination. Since selfefficacy is significant for both intention to vaccinate and receipt of the first vaccination and knowledge of the vaccine was significant with both receiving the first vaccination and

29 23 receiving the first and second, health educational interventions should focus on increasing adolescents ability to over come perceived barriers to vaccination to the HPV vaccination and increase their knowledge about the vaccination itself.

30 24 7. References 1. CDC. Quadrivalent human papillomavirous vaccine: recommendations of the advisory committee on immunization practices (ACOP). MMWR Morb Mortal Wkly Rep 2007;56: Smith J, Lindsay L, Hoots B, Keys K, Franceshi S, Winer R. Human papilomavirus type distribution in invasive cervical cancer and high-grade cervical lesions: meta-analysis update. Int J Cancer 2007;121(3): Shikary T, Bernstein D, Jin Y, Zimet G, Rosenthal S, Kahn J. Epidemiology and risk factors for the human papillomavirus infection in diverse sample of low-income young women. Journal of Clinical Virology 2009;46: Downs L, Smith J, Scarinci I, Flowers L, Parham G. The disparity of cervical cancer in diverse populations. Gynecol Oncol 2008;109(2 Suppl):S22-S Garland S, Hernadez-Avila M, Wheeler C, Perez G, Harper D, Leodolter S. Quadrivalent vaccome against human papillomavirus to prevent anogenital disease. New England Journal of Medicine 2007;356(May 19): Scarinci I, Grarcia F, Kobetz E, Partidge E, Brandt H, Bell M, et al. Cervical Cancer Prevention: New Tools and Old Barriers. Cancer 2010;116(11): Paavonen J, Jenkins D, Bosch F, al. e. Efficacy of a prophylactic adjuvanted bivalent L1 virus-like-particle vaccine against infection with human papillomavirus types 16 and 18 in young women: an interim analysis of a phase II double-blind, randomised controlled trail. Lancet 2007;369: CDC. National and State Vaccination Coverage Among Adolescents Aged 13 Through 17 Years --- United States, MMWR Morb Mortal Wkly Rep 2011;60(33): CDC. National, state, and local area vaccination coverage among adolescents aged years - United States. MMWR Morb Mortal Wkly Rep 2008;36: Cook R, Zhang J, Mullins J, Kauf T, Brumback B, Steingraber H, et al. Factors Associated With Initiation and Completion of Human Papillomavirus Vaccine Series Among Young Women Enrolled in Medicaid. Journal of Adolescent Health 2010;47: Tan W, Viera A, Rowe-West B, Grimshaw A, Quinn B, Walter E. The HPV vaccine: Are dosing recommendations being followed? Vaccine 2011;29: Niccolai L, Mehta N, Hadler J. Racial/Ethnic and Poverity Disparties in Human Papillomavius Vaccination Completion. Am J Prev Med 2011;41(4): Schluterman N, Terplan M, Lydecker A, Tracy K. Human papillomavirus (HPV) vaccine uptake and completion at an urban hospital. Vaccine 2011;29:

31 Marlow LA. HPV vaccination among ethnic minorities in the UK: knowledge, acceptability and attitudes. Br J Cancer 2011;105(4): Reiter PL, Stubbs B, Panozzo CA, Whitesell D, Brewer NT. HPV and HPV vaccine education intervention: effects on parents, healthcare staff, and school staff. Cancer Epidemiol Biomarkers Prev 2011;20(11): Thompson VL, Arnold LD, Notaro SR. African American parents' attitudes toward HPV vaccination. Ethn Dis 2011;21(3): Trim K, Nagji N, Elit L, Roy K. Parental Knowledge, Attitudes, and Behaviours towards Human Papillomavirus Vaccination for Their Children: A Systematic Review from 2001 to Obstet Gynecol Int 2012;2012: Ajzen I. The Theory of Planned Behavior. Organizational Behavior and Human Discision Processes 1991;50: Montano D, Kasprzyk D. Theory of Reasoned Action, Theory of Planned Behavor, and the Intergated Behavioral Model. In: Glanz K, Rimer B, Viswanath K, editors. Health Behavior and Health Education: Theory, Rsearch, and Practice San Francisco, CA: Wiley; p Roberts M, Gerrard M, Reimer R, Gibbions F. Mother-Daughter Commuication and Human Papillomavirus Vaccine Uptake by College Students. Pediatrics 2010;125: Kahn J, Rosenthal S, Hamann T, Bernstein D. Attitudes about human papillovirus vaccine in young women. International Journal of STD & AIDS 2003;14: Philadelphia Health Department. KIDS Immunization Registry. Philadelphia, PA; Retrieved June 12, Gerend M, Magloire Z. Awareness, Knowlege, and Beliefs about the Human Papillomavirus in a Racially Diverse Sample of Young Adults. Journal of Adolescent Health 2008;42: