Acceptability of HPV vaccination among young adults aged 18–30 years–a population based survey in Sweden

Abstract

Acceptability of human papillomavirus (HPV) vaccination seems to be high in the Western world but fewer data are available for men than for women. There are also concerns that HPV vaccination might lead young people to change their healthcare-related behaviours. We investigated these issues in a population-based survey performed in Sweden during January-May, 2007, just after HPV vaccination had been licensed. A total of 10 567 men and women aged 18 to 30 years participated. The intention to accept HPV vaccination among these young adults was relatively high but could likely be improved with higher awareness of HPV-related diseases as well as of the safety and efficacy of vaccines in general. Also, the cost of the vaccine needs to be affordable. Even though few young adults stated their healthcare-related behaviours would change after HPV vaccination, a significant number were uncertain, suggesting a need for continued educational efforts when HPV-vaccinating this group.

Introduction

Infection with oncogenic types of human papillomavirus (HPV) is the main underlying cause of cervical cancer, the second leading cause of death from cancer in women worldwide. Although screening programmes using the Papanicolaou (Pap) test have led to substantial declines in mortality caused by cervical cancer in developed countries, about 230 000 women per year die from the disease worldwide. Even in developed countries, cervical cancer remains the second leading cancer in women younger than 45 years [1]. The sexually transmitted HPV16, followed by HPV18, are found in about 70% of invasive cervical tumours. HPV is also known to cause condyloma acuminate (genital warts) and can cause penile, vulval, anal and head and neck cancers [2].

Two HPV vaccines are now available (the quadrivalent Gardasil^®, Merck and Co., Inc. and the bivalent Cervarix^®, GlaxoSmithKline) and have shown more than 90% efficacy against HPV16 and 18-related precancerous lesions in clinical trials among women aged 15–26 years [3], [4]. The quadrivalent vaccine also confers significant protection (95–100%) against condyloma caused by HPV6 and HPV11 [5]. Even though vaccination of teenage girls before sexual debut is acknowledged as the first priority for vaccination programs [6], many sexually active women could also benefit from catch-up vaccination since only a subset of those women would have been previously exposed to HPV types covered by the vaccine [5]. Furthermore, men act as vectors for HPV infections spreading to their female partners and may also suffer HPV-related morbidity and mortality. It has been reported that men experience a longer duration of condyloma, and incur greater treatment costs than women [7]. In men, up to 80–85% of anal cancers and around 50% of penile cancers have been associated with HPV infection [8]. The incidence of anal cancer is particularly high in men who have sex with men (MSM) but is also increasing among both men and women in the general population [9], [10]. Furthermore, there are indications that the incidence of HPV-positive tonsillar cancer has been increasing in the past decades [11]. Therefore both males and females may benefit from vaccinating males for HPV and clinical trials in males have now begun to show results regarding immunogenicity [12] and high efficacy [13].

In Sweden, HPV vaccination was licensed for both genders in October 2006 but did not gain any momentum until subsidized HPV vaccination was made available in May 2007. Since then, both vaccines are reimbursed by the government for up to 50% of the cost (unreimbursed about 3300 SEK/330 euro for the quadrivalent vaccine and about 2800 SEK/280 euro for the bivalent) for girls aged 13–17 years. In connection with the vaccine being subsidized, marketing aimed at the general public began in June 2007. Television and radio campaigns have since focused mainly on young women and the existence of a vaccine against cervical cancer. There have also been letter campaigns aimed at parents to daughters. Up until now, about 20% of 13–17-year old Swedish girls have elected to get vaccinated, around 98% of which have been immunized with the quadrivalent and 2% with the bivalent vaccine [14]. A free school-based program using the bivalent vaccine, targeting 11–12 year old girls, will be initiated in Sweden in fall of 2010 [15].

In connection to the introduction of HPV vaccines, focus has been directed to the general public's need for information on HPV, especially since it has been shown that knowledge of the link between HPV and cervical cancer is very poor [16], [17]. Some controversial issues regarding HPV vaccination have also been identified; one being potential sexual disinhibition among adolescents and another, a decreased participation in cervical screening among women [18], [19]. However, acceptability of the HPV vaccine has across most studies been high, especially among parents (55–100% with regards to willingness to vaccinate their children [20]), and adult women (50–96% [21]). In a population-based survey among Swedish parents of children aged 12–15 years, we showed that acceptability of HPV vaccination was high, with 76% willing to vaccinate their child if for free and 65% willing even if the vaccine was not for free [22]. Higher vaccine acceptability has been reported among people who believed vaccines are effective, that a physician would recommend it and HPV infection was likely [20]. Among young women, additional predictors include barriers, HPV knowledge, risk, age and marital status [21]. Fewer studies have assessed acceptability of HPV vaccination among male adults. Studies in the US, Australia, Canada and the UK have reported it to range from 33% to 88% [23], [24], [25], [26], [27], which indicates a lower interest than among women. Although there is a relative lack of population-based data, two recent studies in a national sample of US men reported that acceptability was only moderate among heterosexual men (37% willing to get vaccinated) but that it was substantially higher among gay and bisexual men (74% willing) [28], [29]. Correlates to acceptability identified among men have been reported to be similar to those in women and to include perceived likelihood of HPV–related disease and vaccine effectiveness [28], [30].

The aim of the present study, carried out in parallel with our study among parents of children aged 12–15 [22], was to investigate acceptability of HPV vaccination in a large population-based sample of young adults aged 18–30 in Sweden. This population is not very likely to be served by state-financed vaccination programs but has the opportunity to vaccinate at will. The study was also performed to assess perceptions of HPV vaccine and potential changes in healthcare-related behaviours after HPV vaccination.