Predictors of interest in HPV vaccination: A study of British adolescents

Abstract

Human papillomavirus (HPV) vaccination is now offered to adolescent girls in the UK. Adolescents over 16 years old are likely to make their own decision about the vaccination. The purpose of this cross-sectional study was to assess acceptability of HPV vaccination among female adolescents (16–19 years) and investigate socio-cultural variation in intended acceptance. Participants were recruited through two further-education colleges in England. They read information about HPV before responding to questions assessing acceptability, demographics and attitudes based on the Health Belief Model. There were 367 cases included in analyses. Most participants said they would be likely to accept HPV vaccination (89%). Ethnicity, religion and English as a first language were associated with acceptability (pseudo-R² = 0.11). In multivariate analysis only religion remained significant, with girls from Muslim (OR = 0.20, CI: 0.05–0.90) or Hindu/Sikh (OR = 0.09, CI: 0.01–0.56) backgrounds less likely to accept vaccination. Perceived susceptibility, benefits and barriers were also associated with acceptability (pseudo-R² = 0.25), but did not mediate the effect of the ethnicity-related variables. Interventions based on the health belief model may help encourage HPV vaccine acceptance among adolescents. Future research to understand the issues associated with HPV vaccination in different religious groups is needed.

Introduction

In the UK, routine HPV vaccination is now offered to all girls age 12–13 years, with a ‘catch-up’ for adolescent girls up to 18. There have been a number of studies assessing parental attitudes to HPV vaccination, with a generally favourable response (e.g. [1], [2], [3]) and a recent feasibility study in the UK achieved a 69% uptake for the first two doses of the vaccine [4]. Vaccinating the younger adolescents (under 16 years) will in most cases require parental consent, however under section 8 of the family law reform act 1969, the consent to medical treatment of an adolescent who has reached the age of 16 “shall be as effective as it would be if he were of full age [and] it shall not be necessary to obtain any consent for it from his parent or guardian” [5]. Furthermore, the ‘Green Book’, which provides guidance about vaccination in the UK, explicitly states that parental consent is not required for vaccinating adolescents over 16 years old [6]. It is therefore likely that 16–18 years old offered the HPV vaccine as part of the catch-up programme will take the primary decision-making role themselves. To date there have been few studies assessing attitudes to HPV vaccination or predictors of acceptability in this age group.

In one study of students aged 18 and over, 74% said they would have HPV vaccination after reading information about it [7]. Factors associated with acceptability were perceived susceptibility to HPV, having had more sexual partners, not being scared of needles, and believing the vaccine would be safe and inexpensive. In a more recent study of HPV vaccine acceptability among 14–15 years old in Finland, 83% said they would have the vaccine, with low knowledge of HPV and Chlamydia being predictors of non-acceptability [8]. There have been several studies in the US assessing adolescent attitudes to vaccines against sexually transmitted infection (STI) in general. One study considered adolescents’ (12–17 years) attitudes to vaccines against gonorrhoea, genital herpes and HIV. Around 90% of adolescents said they would accept a vaccine against one of these STIs, and predictors of acceptability were older age, believing that their parent wanted them to have the vaccine, and being sexually active [9]. In a study assessing predictors of Hepatitis B vaccine uptake using actual behaviour as the outcome [10], 51 out of 80 adolescents aged 11–18 years received the first dose of the vaccine series. Those who had the vaccine were more likely to believe it was important to their care provider and their parents, and that ‘everyone’ should have the vaccine. In general then, adolescent acceptability of vaccines for HPV and other STIs seems to be high, with a variety of beliefs, attitudes and behavioural and demographic factors predicting acceptability. However, no study has yet been carried out in the UK, and many studies have lacked a theoretical framework.

The health belief model (HBM [11]) is a model for understanding health-related behaviour. In particular the HBM suggests health behaviour is predicted by attitudes towards a health threat (perceived severity of the threat and susceptibility to the threat) and attitudes towards behaviour that can reduce or prevent the threat (perceived benefits of and barriers to performing the behaviour). Many early studies using the HBM focused on preventive behaviours including polio and influenza vaccination [12] and “obtaining vaccination against infectious diseases represents precisely the kind of preventive health behaviour toward which the archetypical HBM was directed” ([13] p. 3). Several studies of HPV vaccine acceptability among parents have used the HBM (e.g. [14], [15]) and a recent review summarized the findings of HPV vaccine acceptability studies using a theoretical approach based around the HBM [2]. The model has also been applied to one study which assessed intention to receive an HIV vaccine among adolescents aged 13–18 years old, finding perceived susceptibility to HIV, perceived benefits of the vaccine, and perceived barriers to vaccination to be predictors of acceptability [16].

An additional proposition of the HBM is that demographic factors can have an influence on attitudes (i.e. perceived threat, and perceived barriers/benefits). Because HPV is an STI and cultures differ in their sexual attitudes and norms, it could be hypothesised that cultural variables (e.g. ethnicity and religion) might be important when considering attitudes about HPV and vaccination. Support for this comes from studies of ethnic minority attitudes to HPV testing where some women felt it reflected “non-traditional cultural or religious practices concerning sex and monogamy” ([17] p. 44) and from ethnic differences in use of sexual health services, where a major barrier for South Asian and African minorities is “the cultural taboo around discussion of sexual matters” ([18] p. 398). More specifically, in a qualitative study with ethnic minority mothers, some believed their daughter's susceptibility to HPV vaccination would be low because of their religious beliefs about sexual abstinence until marriage [19]. Another study has shown that ethnic minority parents are more likely to believe that HPV vaccination will result in an increase in risky sexual behaviour, a belief that has been shown to be a barrier to HPV vaccination [20]. Although some studies have not found any differences in HPV vaccine acceptability on the basis of ethnicity [2], [3], uptake of HPV vaccination in the UK pilot found lower coverage in schools with a greater proportion of ethnic minority pupils [4]. If ethnicity is associated with HPV vaccine acceptability, differences between groups could be mediated at least in part by attitudes.

Given that older adolescents aged 16–18 years in the UK will probably take the lead role in deciding about HPV vaccination, we wanted to explore attitudes to HPV vaccination and predictors of HPV acceptability in this age group. The HBM offers a useful theoretical approach through which to do this, suggesting important constructs that may, alongside demographic variables, play a role in acceptability. The aims of this study were threefold:

• To explore demographic predictors of HPV vaccine acceptability.

• To explore HBM constructs (perceived susceptibility, perceived severity, barriers and benefits) as predictors of HPV vaccine acceptability.

• To test the hypotheses that demographic/cultural differences in acceptability are explained by attitudinal factors.