Factors related to Israeli lesbian women's intention to be vaccinated against human papillomavirus

Abstract

Summary

Lesbian women's susceptibility to human papillomavirus infection and, as a consequence, to cervical cancer, is similar to that of heterosexual women. However, little is known about factors related to lesbian women's intention to be vaccinated against human papillomavirus. The aim of the study was to identify factors related to Israeli lesbian women's intention to be vaccinated, using the Health Belief Model. The study has a cross-sectional design. A convenience sample of 207 lesbian women recruited at clubs in central Israel's lesbian community completed a questionnaire, based on the Health Belief Model. Thirty-two percent of the respondents reported having a high intention to be vaccinated. Perceived susceptibility to cervical cancer and perceived benefits of human papillomavirus vaccination were found to be related to intention to be vaccinated. The findings offer insights that can inform health care providers of strategies to promote vaccination against human papillomavirus in this unique population.

Keywords

Lesbian women sexually transmitted infection HPV human papillomavirus vaccination the Health Belief Model

Introduction

Cervical cancer is the third most common malignancy in the Western world.¹ About 75% of cervical cancer cases are caused by strains 16 and 18 of genital human papillomavirus (HPV).² Genital HPV is one of the most prevalent sexually transmitted infections (STI) in several countries worldwide.³ Cervical cancer caused by oncogenic HPV strains is preventable by vaccination against these strains.²

Israel was traditionally considered to have among the lowest prevalence of cervical cancer compared to that in other Western countries, due to the conservativism of Israeli society.⁴ However, it has been demonstrated that the incidence rates for premalignant lesions among Israeli women are similar to those among women in other Western countries.⁵

There is evidence that 13%−30% of lesbian women are infected with HPV,⁶ even those who never had sexual relations with men.⁷ The term “lesbian” describes women's sexual identity, while “women who have sex with other women” describes sexual behaviour. Sexual identity is not necessarily an indication of sexual behaviour – a considerable number of lesbian women have a history of sexual relations with men.⁸ For purposes of operationalizing the term, the present study will use the term “lesbian” to designate women who have sex with other women. No data exist concerning the extent of this population in Israel.

The prevalent view is that lesbian women are not susceptible to STI, because their sexual relations are perceived as not involving penetration.⁹ However, there is evidence that lesbian women are susceptible to STI to the same degree as all other women. Among risk factors for STI among lesbian women are having current or former heterosexual relations, belief that sex between women is a low-risk activity, and low usage rates for protective measures.¹⁰ The tendency of lesbian women to perceive themselves as being at a low risk for HPV infection may be a barrier to taking preventive actions, such as being vaccinated against HPV.^11–13 Compared to heterosexual women, lesbians may be at greater risk for HPV and cervical cancer due to health and lifestyle factors associated with poor overall health. Lesbians are less likely to regularly visit a reproductive health specialist and are therefore less exposed to information about HPV and referral to HPV vaccination.¹⁴

HPV vaccination was approved for use in Israel by the Ministry of Health in 2007.¹⁵ Both Cervarix (GSK), the bivalent vaccine (against strains 16 and 18), and Gardasil (MSD), the quadrivalent vaccine (against strains 6, 11, 16, and 18), are available in Israel. The vaccine is indicated for women aged 9–26.¹⁶ Since the introduction of the vaccine in the country, Israelis' level of awareness has increased,¹⁵ but the actual vaccination rate has remained low, at approximately 10%.¹⁷ In Israel, vaccinations are either funded through the government national health coverage or available to all residents at a set, subsidized price through supplemental health plans. The HPV vaccines are covered only through the supplemental plans.¹⁵

Better understanding of the decision-making process related to Israeli lesbian women's intention to be vaccinated against HPV will enable health care providers and policy makers to develop effective strategies for promoting vaccination among this unique population.

The conceptual framework

The Health Belief Model (HBM) was originally created to explain and predict preventative health behaviours.¹⁸ The HBM has been widely used to examine initiation and maintenance of health behaviour.¹⁹ According to the model, a number of variables are associated with the likelihood of taking action to detect or prevent the occurrence of disease. The HBM has five main constructs: perceived susceptibility, perceived severity, perceived benefits, and barriers, and health motivation. Thus, an individual will likely take a preventable action if he/she perceives his/her susceptibility to a condition as high, the benefits of taking a particular action as exceeding the barriers, and the condition as serious enough (including harmful consequences in regard to personal physical health). The model also refers to health motivation. Unlike the other constructs that relate to beliefs about behaviours, health motivation (representing the general tendency of an individual to engage in health behaviours) is concerned directly with behaviours.²⁰

Several studies used the model to explore factors related to HPV vaccination among the general female population and found it to be generally predictive of the intention to be vaccinated^21,22 or of HPV vaccine acceptability.²³ A systematic review of the HPV vaccine acceptance literature in the US revealed that the HBM has demonstrated applicability to understandings of HPV vaccine acceptance.²⁴ To date, little is known about factors related to lesbian women's intention to be vaccinated against HPV. Therefore, the aim of the study was to identify factors related to Israeli lesbian women's intention to be vaccinated, using the HBM. Based on the literature review, other factors such as knowledge of HPV vaccination, age, heterosexual relationships, and reception of information on HPV vaccination were also investigated.

Methodology

The study has a cross-sectional design. A convenience sample of lesbian women was recruited at clubs of the lesbian community in central Israel. The inclusion criteria were Hebrew written comprehension, self-identification as a lesbian, and being aged 18–26. Each one of the researchers attended a different club, so that the possibility of approaching the same woman more than once was minimal. Two-hundred and thirty women were approached by the researchers, of whom 207 agreed to participate in the study and completed a questionnaire, for a response rate of 90%. Before administering the questionnaire, the researchers verified whether the participants had not previously completed it. It took no longer than 10 minutes to complete the questionnaire. The participants completed the questionnaires and returned them to the researchers immediately. The data were collected over a period of six months during 2012–2013. The participants received an explanation about the purpose of the research and were assured anonymity. Verbal informed consent was obtained from the participants. The study was approved by the ethics committee of Tel-Aviv University.

Instrumentation

The study instrument was a questionnaire based on the HBM, consisting of 53 items. Twenty items examined socio-demographic data, sexual experience with men (yes or no), vaccination against HPV (yes or no; and if yes, how many shots), having received information on HPV vaccination (yes or no), and from whom. Four items examined knowledge of HPV vaccination.

The main part of the questionnaire (consisting of 29 items) is based on the questionnaire of Ben-Natan and Adir,²⁵ who investigated Israeli women's intention to undergo a Pap smear test. The original questionnaire was changed according to the literature review and was adapted for HPV vaccination. The questionnaire was based on the HBM and consisted of five parts: (1) Perceived susceptibility to cervical cancer (typical item: “My chances of getting cervical cancer are low”), (2) perceived severity of this condition (typical item: “Cervical cancer is a lethal disease”), (3) perceived benefits (typical item: “Vaccination will give me a sense of security”), (4) barriers to HPV vaccination (typical item: “I'm afraid that if my sexual orientation is revealed on examination, the doctor will discriminate against me”), and (5) health motivation (typical item: “I usually lead a healthy lifestyle”). These health beliefs, along with knowledge of HPV vaccination, are the main independent research variables. The dependent variable – the likelihood of behavioural change – was assessed by intention to be vaccinated (typical item: “I intend to be vaccinated”). Items representing health beliefs and intention to be vaccinated were rated on a six-point Likert scale ranging from 1 “strongly disagree” to 6 “strongly agree”. For the majority of the subscales, higher scores indicated more positive health beliefs, but for barriers to vaccination, higher scores indicated more negative health beliefs. Items on knowledge of HPV vaccination were rated on a dichotomous true-false scale. Each correct answer provided 1 point, for a maximum of 4 points.

The questionnaire was reviewed by three nurse experts in the field of HPV vaccination and was corrected and amended according to their comments. The questionnaire demonstrated satisfactory face validity and internal consistency. Cronbach's alpha for the whole scale was 0.85 and for the subscales ranged between 0.70 and 0.90.

Data analysis

The Statistical Package for Social Sciences (SPSS-PC, version 14, SPSS Inc., Chicago, IL, USA) was used to analyze the data. Forty-two respondents reported being vaccinated against HPV, partially or the full dose, therefore, they were not included in some of the statistical analyses. To test theoretical relationships between the research variables and intention to be vaccinated, Pearson's correlations were used. Independent samples t-tests were used to examine the differences in health beliefs, knowledge of HPV vaccination, and intention to be vaccinated between different groups. Statistical significance was set at p < 0.05.

Results

Respondents' characteristics

The respondents' mean age was 24 (SD = 0.2, range 18–26). Most of them (92%) were Jewish, secular (89%), and unmarried (91%). Most of them (91%) were born in Israel. Fifty-seven percent were of Ashkenazi descent, and the rest of Sephardic descent. The majority (66%) had an academic degree. Fifty-two percent defined their level of income as below average, 27% defined it as average, and the rest as above average.

Health beliefs, knowledge of HPV vaccination, and intention to be vaccinated

Twenty percent of the respondents (n = 42) reported being vaccinated against HPV, whether partially or a full dose. The means of health beliefs, knowledge of HPV vaccination, and intention to be vaccinated, among the unvaccinated respondents (n = 165), are presented in Table 1. It shows that there is a great variance in respondents' intention to be vaccinated (as revealed by wide standard deviations). Thirty-two percent (n = 52) reported having a high intention to be vaccinated. There is also a great variance in respondents' perception of their susceptibility to cervical cancer and in their perception of the benefits of HPV vaccination. In contrast, there is a relative homogeneity in respondents' perception of the severity of cervical cancer (most agreed that it is a severe disease), of barriers to HPV vaccination (most disagreed that various barriers prevent them from being vaccinated), and in respondents' health motivation (most reported that they generally lead a healthy lifestyle).

Table 1.

Differences in health beliefs and knowledge: in vaccinated versus vaccinated (n = 207).

	Unvaccinated (n = 165)		Vaccinated (n = 42)
	Mean	SD	Mean	SD	T	p Value
Variable^a
Intention^b	3.6	1.6
Susceptibility	4.1	1.3	4.6	1.2	−2.35	0.0200
Severity	4.9	1.1	4.7	1.1	0.71	0.4800
Benefits	3.4	1.4	4.5	0.9	−4.66	0.000
Barriers	2.1	0.8	1.8	0.8	1.79	0.0740
Health motivation	4.0	1.0	3.9	.90	0.410	0.684
Knowledge	3.1	0.8	3.3	0.9	−1.40	0.1650

^aRange for intention and all health beliefs: 1–6; range for knowledge: 0–4.

^bCalculated only for unvaccinated respondents.

The respondents' mean score on knowledge of HPV vaccination was medium-high (with narrow standard deviation). The majority gave correct answers to the knowledge questions asked. However, half the respondents answered “no” to the question of whether a woman can contract HPV during sexual intercourse with another woman.

Factors related to unvaccinated respondents' intention to be vaccinated

To test theoretical relationships between unvaccinated respondents' health beliefs, knowledge of HPV vaccination, and their intention to be vaccinated, Pearson's correlations were used. Perceived susceptibility (r = 0.38, p < 0.01) and perceived benefits (r = 0.67, p < 0.01) were the only factors that had statistically significant correlations with intention to be vaccinated. Perceived severity (r = 0.14, p > 0.05), perceived barriers (r = −0.11, p > 0.05), health motivation (r = 0.11, p > 0.05), and knowledge of HPV vaccination (r = 0.12, p > 0.05) were found to have weak and statistically insignificant correlations to intention to be vaccinated. Additionally, no statistically significant correlation was found between respondents' age and their intention to be vaccinated (r = −0.11, p > 0.05).

Differences between unvaccinated and vaccinated respondents

Independent samples t-tests were used to examine the differences in health beliefs and knowledge between unvaccinated and vaccinated respondents. The results are presented in Table 1. It shows that perceived susceptibility to cervical cancer (p < 0.05) and perceived benefits of HPV vaccination (p < 0.001) were the only variables found to be significantly higher among vaccinated respondents.

Sexual experience with men

Sixty percent of the respondents (n = 124) reported having had sexual relationships with men. Unvaccinated respondents who reported having had such experience were found to have a higher intention to be vaccinated (M = 3.8, SD = 1.75) than those who did not report such experience (M = 3.2, SD = 1.39; t(163) = −2.5, p < 0.01).

Receiving information on HPV vaccination

Finally, 64% of the respondents (n = 132) reported having received information on HPV vaccination. The most significant sources of information were the media (noted by 70% as a source of information), followed by female friends (noted by 52%). In contrast, only 37% reported that they had received this information from a doctor, and only 17% from a nurse. Unvaccinated respondents who reported having received information on HPV vaccination were found to have a higher intention to be vaccinated (M = 3.8, SD = 1.61) than those who had not (M = 3.0, SD = 1.61; t(152) = −3, p < 0.05).

Discussion

The present study examined factors related to Israeli lesbian women's intention to be vaccinated, using the HBM. Perceived susceptibility to cervical cancer and perceived benefits of HPV vaccination were the only studied HBM constructs found to be related to respondents' intention to be vaccinated. Perceived susceptibility to HPV and perceived benefits of HPV vaccination have been observed as related to intention to be vaccinated in other studies among general young adult populations,^21,23 and among lesbian women in particular.²⁶

Perceived severity of cervical cancer, perceived barriers to HPV vaccination, and health motivation were found to be unrelated to intention to be vaccinated in the present study. However, in other studies among general female populations,^27,28 these were found to be related. One possible explanation for the lack of association between these constructs and intention to be vaccinated is the homogeneity in respondents' perception of the severity of cervical cancer (most agreed that it is a severe disease), of barriers to HPV vaccination (most disagreed that various barriers prevent them from being vaccinated), and in respondents' health motivation (most reported that they generally lead a healthy lifestyle). In contrast, there is a great variance in respondents' perception of their susceptibility to cervical cancer, in their perception of the benefits of HPV vaccination, and in their intention to be vaccinated. Homogeneity in respondents' knowledge of HPV vaccination (most gave correct answers) and in their age (most were young adults) may also explain the lack of association between knowledge, age, and intention to be vaccinated, although other studies did find such associations.^29–31

Respondents who reported having had sexual relationships with men were found to have a higher intention to be vaccinated than those who had not. Having current or former heterosexual relations is considered a risk factor for STI.¹⁰ It is possible that respondents who had current or past heterosexual relationships considered themselves more susceptible to HPV infection, as such relationships may involve penetration.⁹ In contrast, half the respondents answered “no” to the question of whether a woman can contract HPV during sexual intercourse with another woman, probably because lesbian sexual relations are perceived as not involving penetration.⁹

Unvaccinated respondents who reported having received information on HPV vaccination were found to have a higher intention to be vaccinated than those who had not. Knowing more about HPV has been shown to encourage lesbian population to be vaccinated against HPV.^26,32 Most of the respondents noted the media as a source of information on HPV vaccination. It should be noted that a third of respondents have never received such information from any source. While several studies on lesbian women demonstrate the importance of a physician's recommendation and referral as factors influencing an individual's decision to be vaccinated,^26,32 only a minority of the respondents reported health care providers as sources of information on HPV vaccination. Due to a lack of data for comparison, it is unclear whether this finding reflects Israeli health care providers' practices in general or whether it reflects some kind of discrimination or unawareness of lesbian patients' needs. There is evidence in the literature that health care providers refrain from raising the issue of sexual health among lesbian women, due to lack of knowledge and training,⁷ and feel more uncomfortable with STI in lesbian women than with STI in heterosexual women.¹⁰ While Israel has an active gay and lesbian community, much of the country hold conservative social values, and homosexuality is not widely accepted.³³ Resultantly, this finding may also explain lesbian women's limited contact with health care providers.⁷

Twenty percent of the respondents reported having been vaccinated against HPV. Among the unvaccinated respondents, only 32% had a high intention to be vaccinated. The percentage of vaccinated respondents in the present study is lower than that reported in US studies on lesbian population.^32,34 Similarly, the percentage of respondents who intended to be vaccinated was also lower than previously reported.³⁵ The study findings suggest that the lower intention to be vaccinated and lower actual vaccination rates among Israeli lesbians may be attributed to this population's unawareness to its susceptibility to cervical cancer and its doubts about the benefits of the HPV vaccination. Since the percentages of respondents who reported being vaccinated and of those who had a high intention of being vaccinated are similar, it can be assumed, with caution, that Israeli lesbian women's intention to be vaccinated against HPV reflects actual behaviour. Past research has found vaccine intention to be a significant, reliable predictor of future health behaviour.^36,37

These findings offer insights that can inform health care providers of strategies to promote vaccination against HPV in lesbian women. The findings show that lesbian women's awareness of their susceptibility to HPV and of strategies to prevent it should be raised. In encounters with this population, health care providers should emphasize susceptibility to HPV and its consequences and benefits of HPV vaccination, as these are factors found to be related to lesbian women's intention to be vaccinated. The media is a common and easily accessible source of information, however, no source can serve as a substitute for health care providers. Therefore, efforts should be made by health care providers to address the issue of HPV among this unique population.

Further research on lesbian women's vaccination against HPV is warranted. Comparison to heterosexual women and investigation of health care providers' role in lesbian women's decision to be vaccinated may help better understand this phenomenon.

Finally, the research findings show that the HBM reveals only two factors related to lesbian women's intention to be vaccinated against HPV. Therefore, other theories of health behaviour should be considered as conceptual frameworks of future research in this field.

The present study has several limitations. These include the cross-sectional design and the small convenience sample of lesbian women, factors that may limit conclusions about causality, and generalizability of the findings. Additionally, the research instrument was a self-report questionnaire, and thus the results might have been biased by social desirability. Finally, the study did not address additional constructs of the HBM such as cues to action and self-efficacy.

Footnotes

Conflict of interest

The authors declare no conflict of interest.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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