Original Research
Human Papillomavirus Vaccine Increases High-Risk Sexual Behaviors: A Myth or Valid Concern
The Journal of School Nursing 2014, Vol. 30(6) 456-463 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1059840513520042 jsn.sagepub.com
Nop T. Ratanasiripong, PhD, RN, CCRC1
Abstract In 2006, the first human pappilomavirus (HPV) vaccine was approved for females aged 9 to 26. However, the national HPV vaccination rate among young women has been low. Public concerns were raised in regard to the fact that HPV vaccination might encourage unsafe sex. This cross-sectional study examined the differences in sexual practices between college women who have and have not obtained the HPV vaccine. Participants were 209 vaccinees and 175 nonvaccinees. A web-based survey was used. Sexual practices (numbers of sexual partners in a lifetime and in the past 12 months, condom use, condom use frequency) were not significantly different between the two groups. Among the vaccinees, the numbers of sexual partners before and after vaccination was also not significantly different. School nurses are at the frontier to advise young girls/parents on HPV vaccination before the girls engage in sexual intercourse. They may utilize these findings to address the misunderstanding that HPV vaccination encourages unsafe sex. Keywords human papillomavirus, HPV vaccine, sexual behavior
Introduction It is estimated that 110 billion Americans have been infected by a sexually transmitted infection (STI) and 20 million Americans are newly infected each year (Center of Disease Control and Prevention [CDC], 2013a). Of the 20 million newly infected Americans, 50% are individuals between 15 and 24 years of age. The health care cost of STIs is approximately 16 billion dollars per year (CDC, 2013a). Interventions for prevention of STIs are critically needed and should start early with adolescent and young adult population. Nurses and health care providers who care for students in schools and colleges are in the ideal position to strategically provide education and intervention to the students in order to decrease STI-related negative consequences and health care cost. Of the 32 STIs, the most common STI among sexually active individuals is genital human papillomavirus (HPV) infection (CDC, 2013b). It is estimated that 79 million Americans are infected by HPV and over 9 million of these individuals are between the age of 15 and 24 (CDC, 2013b; Weinstock, Berman, & Cates, 2004). In American women of age 14 to 59, the overall HPV infection prevalence rate is 26.8%. The highest HPV prevalence peak (44.8%) is among the 20- to 24-year-old women (Dunne et al., 2007). In addition, a study found that a cumulative 12-month incidence of HPV infection was 37.2% among the college women who
had their first sexual intercourse during the course of the study (Winer et al., 2006). Currently, there are more than 130 HPV types identified. Of these, over 40 types infected the genital system (Munoz et al., 2003). The genital HPVs are divided into two categories: (1) low-risk types resulting in minor abnormalities at the cervix and genital warts and (2) high-risk types associating with precursor lesions and anogenital cancers, specifically cervical cancer (Stanley, 2010). HPV infections are generally not serious because 70–90% of the infections may either resolve by its own or become unappreciable over time (Ault, 2006; Frazer et al., 2006). However, if the infection becomes persistent, it can cause emotional and physical distress at the individual level and also result in increased health care costs for invasive procedures to remove precancerous and cancerous lesions. Similar to other STIs, the risk factors for acquiring genital HPV infection are mainly related to sexual behaviors,
1
School of Nursing, California State University, Dominguez Hills, CA, USA
Corresponding Author: Nop T. Ratanasiripong, PhD, RN, CCRC, School of Nursing, California State University, Dominguez Hills, 1000 E.Victoria st, P.O. Box 21930 Long Beach, CA 90801, USA. Email: [email protected]
Downloaded from jsn.sagepub.com at DALHOUSIE UNIV on June 24, 2015
Ratanasiripong
457
including younger age, early age of sexual initiation, inadequacy of condom use, having multiple sexual partners, having new sexual partners, and having partners who have multiple sexual partners or have been infected by HPV (CDC, 2007; Dunne et al., 2007; Stanley, 2010). Physiologically, adolescent and young women may mostly be hypothetically at risk because of the cervical maturation process following menarche (Frazer et al., 2006). During this normal process, the squamous columnar junction of the cervix (transformation zone) goes through the process of rapid cell differentiation and replication, which becomes a natural host to HPV (Frazer et al., 2006). If a woman initiated sexual intercourse with an HPV-infected partner during this process, her risk of acquiring HPV may be increased. Most young college students are living away from home with minimal supervision from adults; they are in an environment that is easier to engage in unprotected and highrisk sexual behaviors. The 2010 National College Health Assessment reported that most college women (69.9%) have had vaginal intercourse. Most of them (86%) are single and only 10% are married or in a long-term relationship. Close to a quarter (24%) of college women have more than two sexual partners within the last year (American College Health Association [ACHA], 2010). Among college women who had vaginal intercourse within the last 30 days, 40.7% inadequately used STI-protective barriers, including condoms (ACHA, 2010). Currently, HPV infection is not curable. The clinical practice strategy focuses on early detection of precancerous lesions through routine Papanicolau (Pap) test. If high-grade precursors are identified, medical intervention is then provided to reduce the risk of HPV-related cervical cancer (Association of Reproductive Health Professionals [ARHP], 2009). However, the financial burden is heavy. In the United States, the estimated annual cost for routine Pap test and treatments of pervasive and invasive cancerous lesions is between 1 to 6 billion dollars—adding tremendous financial burden to the U.S. health care system (Frazer et al., 2006). Although regular and consistent use of condoms provides 60% protection against HPV infection, HPV can still be sexually transmitted through unprotected genital skin areas such as the vulva or the scrotal sacs (Winer et al., 2006). The only primary prevention method among sexually active individuals is to obtain an HPV vaccine. Currently, there are two HPV vaccines approved for use in the United States: Gardasil1 and Cervarix1. Gardasil is recommended for females between 9 and 26 years of age. Routine vaccination with a series of three doses is recommended for girls between 11 and 12 years of age and ‘‘catch-up’’ vaccination is suggested for females between 13 and 26 years of age. Cervarix is recommended for females between 10 and 25 years of age (CDC, 2010a). Both vaccines are highly effective against two high-risk HPV types (16 and 18) that are associated with cervical/vaginal cancers (CDC, 2010a). In 2009, Gardasil
was also approved for prevention of genital warts and anogenital cancers among males between 9 and 26 years of age (FDA, 2010). When Gardasil was first approved in 2006, it is considered to be a ‘‘research breakthrough’’ (Thomas, 2008, p. 429). In the long term, the vaccine seems to be a costeffective prevention strategy that can strengthen both adolescent health and the quality of their adulthood (Rothman & Rothman, 2009). However, recent studies still reported low HPV vaccination rates; only 30–49% of young females have initiated the HPV vaccination or received at least one dose of the vaccine (California State University-Long Beach [CSULB], 2011; Licht et al., 2010; Roberts, Gerrand, Reimer, & Gibbons, 2010). National data similarly show low vaccination rates. For adolescent females between 13 and 17 years of age, less than half (44.3%) have initiated the vaccination and only a quarter (26.7%) has received three doses of HPV vaccine (CDC, 2010b). For young adult female between 19 and 26 years of age, the HPV vaccine initiation rate is even lower at 17.1% (CDC, 2011). In addition, proposals for mandatory HPV vaccination have instigated some controversy. It was discussed that adolescents may misunderstand that HPV vaccine also provides protection against other STIs. Various groups (e.g., religious groups, conservative politicians) have expressed concerns that receiving HPV vaccine could encourage unsafe sexual practices as well as promote premarital sex (Bailey, 2008; Hager, 2009; Rothman & Rothman, 2009; Vamos, McDermott, & Daley, 2008). Evidence examining factors affecting sexual behaviors/ practices (e.g., number of sexual partners in lifetime or within recent years) among young women have been limited and somewhat outdated. One national study conducted in 1992 among 8,450 males and females between 14 and 22 years of age found that most participants had more than one sexual partner in their lifetime (Santelli, Brener, Lowry, Bhatt, & Zabin, 1998). Alcohol and illicit drug use as well as young age at sexual initiation increased the odds of females having more than one sexual partner in the past 3 months (Santelli et al., 1998). Specific data on sexual behaviors of women who have not received HPV vaccine compared to women who have been vaccinated is even more limited. This article is published as a second part of the original research study to determine factors predicting the HPV vaccination rate and to examine HPV-related sexual behaviors among college women. The first article published the predictors of the vaccine uptake and the intention to obtain the vaccine (Ratanasiripong, Cheng, & Enriquez, 2013). This second article addresses one of the concerns related to the HPV vaccine mandatory proposal by (1) examining the differences in sexual behaviors between college women who have received (vaccinees) and have not received the HPV vaccine (nonvaccinees) and (2) examining the postvaccine sexual practices among the vaccinees.
Downloaded from jsn.sagepub.com at DALHOUSIE UNIV on June 24, 2015
458
The Journal of School Nursing 30(6)
Method Study Setting and Sample The sample for this cross-sectional study consisted of undergraduate female college students at a public university in California where the student body is diverse. The students must be between 18 and 26 years old; the maximum age limit coincided with the maximum age to receive HPV vaccine. The university’s Enrollment Services provided a random sampling of undergraduate female students’ e-mail addresses. Then, the e-mail addresses were categorized by the identified ethnicities; Caucasian, African American, Hispanic, and Asian. A sample within each ethnicity was chosen by using an SPSS version 19.0 program to randomly select 800 of the retrieved e-mail addresses. In the African American group, only 674 eligible students were enrolled on campus. Thus, a total of 3,074 e-mail addresses were obtained. The approval for this study was obtained from California State University, Long Beach’s Institutional Review Board.
Data Collection An invitation to participate in the study was e-mailed to 3,074 potential participants in Spring 2012. The invitation contained limited information about HPV and the purpose of the study in order to minimize self-selection bias and enhance honest answers to sexual behavior questions. The study purpose on the invitation was generalized and simplified as ‘‘the purpose of this study is to examine what college women know, think, and do about HPV and HPV vaccine.’’ The potential participants were asked to click on a web link (SurveyMonkey) if they were interested in participating. The first page on the web-based survey was an informed consent, which included benefits and risks of the study. The informed consent also explained a risk that some questions ask about sexual activities and the participants could decline to answer any question by skipping the question or clicking on the ‘‘prefer not to answer’’ button. At the bottom of the informed consent page, there were two buttons for the potential participants to choose—agree to participate and decline to participate. The SurveyMonkey page would close if the invited participant did not agree to participate. If the invited participant agreed, she was directed to the webpage to complete the survey. The online survey consisted of demographic information (6 items), sexual history (10 items for nonvaccinees and 13 items for vaccinees), and ‘‘HPV/HPV vaccine-related knowledge, attitudes, and behaviors’’ questionnaire. This questionnaire was constructed based on the Theory of Planned Behavior framework. The theorist was consulted for content validity. The face validity was also performed. The questionnaire contained true/false HPV/HPV knowledge statements (9 items), an attitude toward HPV vaccine semantic differential scale (9 items), an attitude toward getting vaccinated against HPV semantic differential scale
(6 items), a subjective norms Likert-type scale (5 items), a perceived behavioral control Likert-type scale (4 items), an intention to vaccinate Likert-type scale (4 items, nonvaccinees only), and 1 vaccination status item. Cronbach’s coefficient as of all scales ranged from .70 to .96. At 1 week and 2 weeks after the study initiation, reminders were e-mailed to all potential participants, except those who asked the researcher not to send reminders. Four weeks after sending out the invitation, the study was closed. To enhance the response rate, a ‘‘prize’’ strategy was also utilized. Each participant had the opportunity to draw a prize if she was one of the first 305 participants to come to the Student Health Services on campus. Information about prizes was noted on the informed consent page. Instructions on how to obtain the prize was written on the last page of the survey.
Data Analysis Statistical Packet for the Social Sciences (SPSS) 19.0 was utilized for data analysis. Participant vaccination status, demographic, sexual history, and sexual behaviors were explored through descriptive statistics. Pearson’s correlation coefficients were utilized to explore the relationships between continuous variables (i.e., age, age of first sexual intercourse, knowledge, attitudes toward HPV vaccine, attitude toward getting vaccinated against HPV, subjective norms, and perceived behavioral control), the number of sexual partners in lifetime, and the number of sexual partners in the past 12 months. Spearman’s r correlation coefficients were used to explore the relationships between categorical variables (i.e., ethnicity, class major, religion, health insurance status, and partner gender), the number of sexual partners in lifetime, and the number of sexual partners in the past 12 months. Analysis of covariance (ANCOVA) was used to examine the mean differences in the number of sexual partners in a lifetime and number of sexual partners in the past 12 months between nonvaccinees and vaccinees. Chi-square tests were used to examine the differences in condom use experience and condom use frequency between the two groups. For vaccinees who have already had sexual intercourse before vaccine initiation, paired t-test was used to examine the mean difference between the number of sexual partners before and after the vaccination.
Results An e-mail invitation was sent to 3,074 undergraduate female students; 800 (26%) Caucasians, 800 (26%) Asians, 800 (26%) Latinos, and 674 (22%) African Americans. Ten of the e-mails were delivery failures. A total of 486 college women responded to the invitation, with 2 students declined to complete the survey. The survey response rate was 15.8%. Among 484 participants, 442 (91.3%) participants were qualified for the study analysis. Forty-two participants were excluded due to one of the following reasons: failing on
Downloaded from jsn.sagepub.com at DALHOUSIE UNIV on June 24, 2015
Ratanasiripong
459
Table 1. Description of Sexual Behaviors Between Nonvaccinees and Vaccinees. M The number of sexual partners in lifetime Entire group (n ¼ 269) 4.37 Nonvaccinees (n ¼ 123) 3.73 Vaccinees (n ¼ 146) 4.90 The number of sexual partners in the past 12 Entire group (n ¼ 270) 1.52 Nonvaccinees (n ¼ 123) 1.44 Vaccinees (n ¼ 147) 1.59
SD
Range
Table 2. Analysis of Covariance for the Number of Sexual Partners in a Lifetime as a Function of Vaccination Status, Using Age of First Sexual Intercourse, and HPV/HPV Vaccine Knowledge as Covariates. Source
4.84 3.70 5.60 months 1.33 1.20 1.43
1–40 1–25 1–40 0–10 0–8 0–10
Age of first sexual intercourse HPV knowledge Vaccination status Error
df
MS
F
p Value
1 1 1 264
531.06 399.50 14.81 19.75
26.88 20.22 0.75
Human Papillomavirus Vaccine Increases High-Risk Sexual Behaviors: A Myth or Valid Concern
The Journal of School Nursing 2014, Vol. 30(6) 456-463 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1059840513520042 jsn.sagepub.com
Nop T. Ratanasiripong, PhD, RN, CCRC1
Abstract In 2006, the first human pappilomavirus (HPV) vaccine was approved for females aged 9 to 26. However, the national HPV vaccination rate among young women has been low. Public concerns were raised in regard to the fact that HPV vaccination might encourage unsafe sex. This cross-sectional study examined the differences in sexual practices between college women who have and have not obtained the HPV vaccine. Participants were 209 vaccinees and 175 nonvaccinees. A web-based survey was used. Sexual practices (numbers of sexual partners in a lifetime and in the past 12 months, condom use, condom use frequency) were not significantly different between the two groups. Among the vaccinees, the numbers of sexual partners before and after vaccination was also not significantly different. School nurses are at the frontier to advise young girls/parents on HPV vaccination before the girls engage in sexual intercourse. They may utilize these findings to address the misunderstanding that HPV vaccination encourages unsafe sex. Keywords human papillomavirus, HPV vaccine, sexual behavior
Introduction It is estimated that 110 billion Americans have been infected by a sexually transmitted infection (STI) and 20 million Americans are newly infected each year (Center of Disease Control and Prevention [CDC], 2013a). Of the 20 million newly infected Americans, 50% are individuals between 15 and 24 years of age. The health care cost of STIs is approximately 16 billion dollars per year (CDC, 2013a). Interventions for prevention of STIs are critically needed and should start early with adolescent and young adult population. Nurses and health care providers who care for students in schools and colleges are in the ideal position to strategically provide education and intervention to the students in order to decrease STI-related negative consequences and health care cost. Of the 32 STIs, the most common STI among sexually active individuals is genital human papillomavirus (HPV) infection (CDC, 2013b). It is estimated that 79 million Americans are infected by HPV and over 9 million of these individuals are between the age of 15 and 24 (CDC, 2013b; Weinstock, Berman, & Cates, 2004). In American women of age 14 to 59, the overall HPV infection prevalence rate is 26.8%. The highest HPV prevalence peak (44.8%) is among the 20- to 24-year-old women (Dunne et al., 2007). In addition, a study found that a cumulative 12-month incidence of HPV infection was 37.2% among the college women who
had their first sexual intercourse during the course of the study (Winer et al., 2006). Currently, there are more than 130 HPV types identified. Of these, over 40 types infected the genital system (Munoz et al., 2003). The genital HPVs are divided into two categories: (1) low-risk types resulting in minor abnormalities at the cervix and genital warts and (2) high-risk types associating with precursor lesions and anogenital cancers, specifically cervical cancer (Stanley, 2010). HPV infections are generally not serious because 70–90% of the infections may either resolve by its own or become unappreciable over time (Ault, 2006; Frazer et al., 2006). However, if the infection becomes persistent, it can cause emotional and physical distress at the individual level and also result in increased health care costs for invasive procedures to remove precancerous and cancerous lesions. Similar to other STIs, the risk factors for acquiring genital HPV infection are mainly related to sexual behaviors,
1
School of Nursing, California State University, Dominguez Hills, CA, USA
Corresponding Author: Nop T. Ratanasiripong, PhD, RN, CCRC, School of Nursing, California State University, Dominguez Hills, 1000 E.Victoria st, P.O. Box 21930 Long Beach, CA 90801, USA. Email: [email protected]
Downloaded from jsn.sagepub.com at DALHOUSIE UNIV on June 24, 2015
Ratanasiripong
457
including younger age, early age of sexual initiation, inadequacy of condom use, having multiple sexual partners, having new sexual partners, and having partners who have multiple sexual partners or have been infected by HPV (CDC, 2007; Dunne et al., 2007; Stanley, 2010). Physiologically, adolescent and young women may mostly be hypothetically at risk because of the cervical maturation process following menarche (Frazer et al., 2006). During this normal process, the squamous columnar junction of the cervix (transformation zone) goes through the process of rapid cell differentiation and replication, which becomes a natural host to HPV (Frazer et al., 2006). If a woman initiated sexual intercourse with an HPV-infected partner during this process, her risk of acquiring HPV may be increased. Most young college students are living away from home with minimal supervision from adults; they are in an environment that is easier to engage in unprotected and highrisk sexual behaviors. The 2010 National College Health Assessment reported that most college women (69.9%) have had vaginal intercourse. Most of them (86%) are single and only 10% are married or in a long-term relationship. Close to a quarter (24%) of college women have more than two sexual partners within the last year (American College Health Association [ACHA], 2010). Among college women who had vaginal intercourse within the last 30 days, 40.7% inadequately used STI-protective barriers, including condoms (ACHA, 2010). Currently, HPV infection is not curable. The clinical practice strategy focuses on early detection of precancerous lesions through routine Papanicolau (Pap) test. If high-grade precursors are identified, medical intervention is then provided to reduce the risk of HPV-related cervical cancer (Association of Reproductive Health Professionals [ARHP], 2009). However, the financial burden is heavy. In the United States, the estimated annual cost for routine Pap test and treatments of pervasive and invasive cancerous lesions is between 1 to 6 billion dollars—adding tremendous financial burden to the U.S. health care system (Frazer et al., 2006). Although regular and consistent use of condoms provides 60% protection against HPV infection, HPV can still be sexually transmitted through unprotected genital skin areas such as the vulva or the scrotal sacs (Winer et al., 2006). The only primary prevention method among sexually active individuals is to obtain an HPV vaccine. Currently, there are two HPV vaccines approved for use in the United States: Gardasil1 and Cervarix1. Gardasil is recommended for females between 9 and 26 years of age. Routine vaccination with a series of three doses is recommended for girls between 11 and 12 years of age and ‘‘catch-up’’ vaccination is suggested for females between 13 and 26 years of age. Cervarix is recommended for females between 10 and 25 years of age (CDC, 2010a). Both vaccines are highly effective against two high-risk HPV types (16 and 18) that are associated with cervical/vaginal cancers (CDC, 2010a). In 2009, Gardasil
was also approved for prevention of genital warts and anogenital cancers among males between 9 and 26 years of age (FDA, 2010). When Gardasil was first approved in 2006, it is considered to be a ‘‘research breakthrough’’ (Thomas, 2008, p. 429). In the long term, the vaccine seems to be a costeffective prevention strategy that can strengthen both adolescent health and the quality of their adulthood (Rothman & Rothman, 2009). However, recent studies still reported low HPV vaccination rates; only 30–49% of young females have initiated the HPV vaccination or received at least one dose of the vaccine (California State University-Long Beach [CSULB], 2011; Licht et al., 2010; Roberts, Gerrand, Reimer, & Gibbons, 2010). National data similarly show low vaccination rates. For adolescent females between 13 and 17 years of age, less than half (44.3%) have initiated the vaccination and only a quarter (26.7%) has received three doses of HPV vaccine (CDC, 2010b). For young adult female between 19 and 26 years of age, the HPV vaccine initiation rate is even lower at 17.1% (CDC, 2011). In addition, proposals for mandatory HPV vaccination have instigated some controversy. It was discussed that adolescents may misunderstand that HPV vaccine also provides protection against other STIs. Various groups (e.g., religious groups, conservative politicians) have expressed concerns that receiving HPV vaccine could encourage unsafe sexual practices as well as promote premarital sex (Bailey, 2008; Hager, 2009; Rothman & Rothman, 2009; Vamos, McDermott, & Daley, 2008). Evidence examining factors affecting sexual behaviors/ practices (e.g., number of sexual partners in lifetime or within recent years) among young women have been limited and somewhat outdated. One national study conducted in 1992 among 8,450 males and females between 14 and 22 years of age found that most participants had more than one sexual partner in their lifetime (Santelli, Brener, Lowry, Bhatt, & Zabin, 1998). Alcohol and illicit drug use as well as young age at sexual initiation increased the odds of females having more than one sexual partner in the past 3 months (Santelli et al., 1998). Specific data on sexual behaviors of women who have not received HPV vaccine compared to women who have been vaccinated is even more limited. This article is published as a second part of the original research study to determine factors predicting the HPV vaccination rate and to examine HPV-related sexual behaviors among college women. The first article published the predictors of the vaccine uptake and the intention to obtain the vaccine (Ratanasiripong, Cheng, & Enriquez, 2013). This second article addresses one of the concerns related to the HPV vaccine mandatory proposal by (1) examining the differences in sexual behaviors between college women who have received (vaccinees) and have not received the HPV vaccine (nonvaccinees) and (2) examining the postvaccine sexual practices among the vaccinees.
Downloaded from jsn.sagepub.com at DALHOUSIE UNIV on June 24, 2015
458
The Journal of School Nursing 30(6)
Method Study Setting and Sample The sample for this cross-sectional study consisted of undergraduate female college students at a public university in California where the student body is diverse. The students must be between 18 and 26 years old; the maximum age limit coincided with the maximum age to receive HPV vaccine. The university’s Enrollment Services provided a random sampling of undergraduate female students’ e-mail addresses. Then, the e-mail addresses were categorized by the identified ethnicities; Caucasian, African American, Hispanic, and Asian. A sample within each ethnicity was chosen by using an SPSS version 19.0 program to randomly select 800 of the retrieved e-mail addresses. In the African American group, only 674 eligible students were enrolled on campus. Thus, a total of 3,074 e-mail addresses were obtained. The approval for this study was obtained from California State University, Long Beach’s Institutional Review Board.
Data Collection An invitation to participate in the study was e-mailed to 3,074 potential participants in Spring 2012. The invitation contained limited information about HPV and the purpose of the study in order to minimize self-selection bias and enhance honest answers to sexual behavior questions. The study purpose on the invitation was generalized and simplified as ‘‘the purpose of this study is to examine what college women know, think, and do about HPV and HPV vaccine.’’ The potential participants were asked to click on a web link (SurveyMonkey) if they were interested in participating. The first page on the web-based survey was an informed consent, which included benefits and risks of the study. The informed consent also explained a risk that some questions ask about sexual activities and the participants could decline to answer any question by skipping the question or clicking on the ‘‘prefer not to answer’’ button. At the bottom of the informed consent page, there were two buttons for the potential participants to choose—agree to participate and decline to participate. The SurveyMonkey page would close if the invited participant did not agree to participate. If the invited participant agreed, she was directed to the webpage to complete the survey. The online survey consisted of demographic information (6 items), sexual history (10 items for nonvaccinees and 13 items for vaccinees), and ‘‘HPV/HPV vaccine-related knowledge, attitudes, and behaviors’’ questionnaire. This questionnaire was constructed based on the Theory of Planned Behavior framework. The theorist was consulted for content validity. The face validity was also performed. The questionnaire contained true/false HPV/HPV knowledge statements (9 items), an attitude toward HPV vaccine semantic differential scale (9 items), an attitude toward getting vaccinated against HPV semantic differential scale
(6 items), a subjective norms Likert-type scale (5 items), a perceived behavioral control Likert-type scale (4 items), an intention to vaccinate Likert-type scale (4 items, nonvaccinees only), and 1 vaccination status item. Cronbach’s coefficient as of all scales ranged from .70 to .96. At 1 week and 2 weeks after the study initiation, reminders were e-mailed to all potential participants, except those who asked the researcher not to send reminders. Four weeks after sending out the invitation, the study was closed. To enhance the response rate, a ‘‘prize’’ strategy was also utilized. Each participant had the opportunity to draw a prize if she was one of the first 305 participants to come to the Student Health Services on campus. Information about prizes was noted on the informed consent page. Instructions on how to obtain the prize was written on the last page of the survey.
Data Analysis Statistical Packet for the Social Sciences (SPSS) 19.0 was utilized for data analysis. Participant vaccination status, demographic, sexual history, and sexual behaviors were explored through descriptive statistics. Pearson’s correlation coefficients were utilized to explore the relationships between continuous variables (i.e., age, age of first sexual intercourse, knowledge, attitudes toward HPV vaccine, attitude toward getting vaccinated against HPV, subjective norms, and perceived behavioral control), the number of sexual partners in lifetime, and the number of sexual partners in the past 12 months. Spearman’s r correlation coefficients were used to explore the relationships between categorical variables (i.e., ethnicity, class major, religion, health insurance status, and partner gender), the number of sexual partners in lifetime, and the number of sexual partners in the past 12 months. Analysis of covariance (ANCOVA) was used to examine the mean differences in the number of sexual partners in a lifetime and number of sexual partners in the past 12 months between nonvaccinees and vaccinees. Chi-square tests were used to examine the differences in condom use experience and condom use frequency between the two groups. For vaccinees who have already had sexual intercourse before vaccine initiation, paired t-test was used to examine the mean difference between the number of sexual partners before and after the vaccination.
Results An e-mail invitation was sent to 3,074 undergraduate female students; 800 (26%) Caucasians, 800 (26%) Asians, 800 (26%) Latinos, and 674 (22%) African Americans. Ten of the e-mails were delivery failures. A total of 486 college women responded to the invitation, with 2 students declined to complete the survey. The survey response rate was 15.8%. Among 484 participants, 442 (91.3%) participants were qualified for the study analysis. Forty-two participants were excluded due to one of the following reasons: failing on
Downloaded from jsn.sagepub.com at DALHOUSIE UNIV on June 24, 2015
Ratanasiripong
459
Table 1. Description of Sexual Behaviors Between Nonvaccinees and Vaccinees. M The number of sexual partners in lifetime Entire group (n ¼ 269) 4.37 Nonvaccinees (n ¼ 123) 3.73 Vaccinees (n ¼ 146) 4.90 The number of sexual partners in the past 12 Entire group (n ¼ 270) 1.52 Nonvaccinees (n ¼ 123) 1.44 Vaccinees (n ¼ 147) 1.59
SD
Range
Table 2. Analysis of Covariance for the Number of Sexual Partners in a Lifetime as a Function of Vaccination Status, Using Age of First Sexual Intercourse, and HPV/HPV Vaccine Knowledge as Covariates. Source
4.84 3.70 5.60 months 1.33 1.20 1.43
1–40 1–25 1–40 0–10 0–8 0–10
Age of first sexual intercourse HPV knowledge Vaccination status Error
df
MS
F
p Value
1 1 1 264
531.06 399.50 14.81 19.75
26.88 20.22 0.75
