In Germany, despite having adopted HPV vaccination in the national immunization schedule in 2007, there is no comprehensive program in place to promote or to monitor vaccine uptake on a national level. In our setting we found that only 41% of interviewed girls had received the recommended 3 doses of HPV-vaccines even though the recommendation was in place for already three years; a considerable proportion had an incomplete vaccination series with more than 12 mo between interview and last vaccine shot. A negative attitude toward vaccinations in general was significantly associated with HPV vaccination status, and there was a significant lack of knowledge related to HPV-infection among girls. Our results highlight the need for more public education on HPV and HPV-vaccines targeting all stakeholders: Parents, students, and healthcare providers.
To the best of our knowledge, this is the first study that assessed knowledge, attitude and practise related to HPV and HPV vaccination among school students in Germany. In several industrialized countries with HPV vaccination recommendation, similar studies have been conducted,16-20
but country-specific data are required to design and implement tailored programs. In our study setting, vaccination coverage was low among young females corroborating data from previous regional surveys in Germany with 42% of female 10th grade students in the city of Essen and 32.8% of school girls in the federal state of Brandenburg.3,4
Therefore, we assume that the identified barriers to HPV vaccine uptake might be generalizable to other settings in Germany, where uptake of other vaccines e.g., against tetanus and measles is usually not a major problem as also indicated in our study.
The German Health Interview and Examination Survey for Children and Adolescents (KiGGS) from 2007 showed a significant difference in vaccination coverage for basic immunization such as tetanus, diphtheria and poliomyelitis among students with and without migration background.12
There was, however, no association of HPV vaccination with migration background in our study population, which might be also due to the small number of participating girls with migration background. In a study investigating the effect of social inequalities on the uptake of HPV vaccine in the UK, the authors found that HPV vaccine uptake was significantly lower in more deprived areas and in ethnic minority girls.21
It will be important in future studies in Germany to record ethnicity on vaccine uptake monitoring activities to complete the panel of possible predictors for HPV vaccination.
During our survey in 2010, the vast majority of participating girls were 15 y old or even older, meaning a period of three years within they could have initiated HPV vaccination before our interviews. Of these, altogether only 59.6% started HPV vaccination so far despite eligibility for vaccination and costs covered by their health insurance. The fact that almost half of them received their first vaccine dose in 2007, the year when the STIKO recommendation for HPV vaccination was endorsed, suggests some positive effects of advertising and advocating in the first year after market launch. Due to the cross-sectional nature of our study, it remains unclear whether the decline in the following years was due to a public debate on HPV vaccine effectiveness and safety that took place in Germany or due to catch-up effects in the first year. Nevertheless, when focusing on the almost 50% of eligible girls that did not initiate HPV vaccination after endorsement of the STIKO recommendation, this may reflect some capability for comprehensive public health campaign focusing on HPV vaccine safety and benefits.
Overall, female students appeared to be more knowledgeable in terms of transmission of HPV than male students. The fact that information campaigns about HPV and the vaccination are targeted only to females so far and HPV vaccination is not recommended and offered to boys may explain this observed gender differences. Vaccinated female students were also more likely to know about the frequency of HPV infection and relationship between cancer and HPV. Being immunised against HPV may lead to an increased awareness and knowledge of the disease (probably through the information material given to female students and parents prior to vaccination). However, given that still one-third of female students were unaware that HPV is sexually transmissible, our results indicate that young females lack fundamental knowledge about this widespread sexually transmitted infection and the vaccination that protects from it. As health beliefs are shown to influence health behaviors,22,23
lack of knowledge regarding HPV infection and vaccination may hinder efforts for prevention.
The vast majority of respondents reported that their preferred source of information on vaccination are first the physician and second the parents, regardless of actual HPV vaccination status. Furthermore, given the fact that the second and third most frequent reason for HPV vaccine refusal was dissuasion by parents and physicians, this underlines the influence of these two peer-groups on adolescent vaccination decision. Our findings are in agreement with published literature that have shown adolescents’ acceptance of a vaccine is associated with their parents´ attitude toward the vaccine, and their perception that parents felt the vaccine is efficient and safe.24,25
In addition, a primary predictor of parental acceptance of a vaccine is recommendation by their child’s healthcare provider.26
Healthcare providers, in particular pediatricians, gynecologists and general practitioners are likely to be influential in educating patients and their parents about HPV infection and the vaccine. Several studies report that parents and general practitioners express general apprehension toward the safety of the vaccine itself and to discuss its usefulness with adolescent girls, often due to its sexual transmission route.27,28
Therefore continuing education for providers who see preadolescent girls in conjunction with a parent or who treat women of school age may be a worthwhile endeavor.
The intention to be vaccinated depends on several factors including individual perceptions and concerns on vaccination, especially HPV vaccine decision. Demographic characteristics such as age, ethnicity, and access to health care may influence initiation of HPV vaccination,29
but also other factors have to be considered. Besides dissuasion by physicians or parents, a frequently reported reason for HPV vaccine declination in our study was concerns about vaccine safety and efficacy. This finding is in line with results of previous studies. Especially the degree of protection against cervical cancer, protection duration, and risk of serious side-effects influence girls HPV vaccination preferences.30
Uptake of HPV vaccines may change considerably if girls are supplied with evidence-based information about these important issues. High levels of vaccine acceptance can be observed if the specific vaccine is recommended by health professionals and supported by the government.27
Therefore, safety and efficacy should be a priority when informing adolescents on vaccines.
Both HPV 16/18 vaccines are expected to protect against approximately 70% of high risk HPV types in most regions worldwide.31
A high efficacy in preventing both HPV 16 and 18 infections and associated precancerous lesions was demonstrated in clinical trials.1,2,32,33
Still, the long-term protective value of HPV vaccination is unknown to date. Post-licensure safety monitoring of the quadrivalent HPV vaccine utilized a large population-based cohort. There was no statistically significant increased risk for any severe event following vaccination such as the development of Guillain-Barré Syndrome (GBS).34
In addition to HPV vaccination, the need for an organized and continuing cervical screening is vitally important. For example, in the UK a comprehensive cervical screening program showed to have reduced HPV-related mortality by up to 80%.35
Despite the major success of cervical screening programmes important limitations have to be recognized. Recent studies showed poor sensitivity of cervical cytology,36
poor predictive value for adenocarcinoma,37
and poor uptake by some communities.38,39
Our study’s results should be interpreted with some limitations. First, our sample is not representative for the student population in Berlin. In preparation of the study we used a purposeful selection process of school classes based on school type. Due to lack of participation of selected classes and schools after several selection rounds to reach the calculated sample size, we decided on a convenience sample of schools neglecting sampling weights in the statistical analyses. In consequence we had a smaller sample size, especially for girls with valid data on the vaccination status and therefore loss of statistical power. Second, the responses and vaccination coverage results may be biased by differential non-response. It can be assumed that students presenting their vaccination card are more likely to be vaccinated than students without the document. Social desirability may also bias in survey research, particularly if respondents lacked privacy during the paper-questioning in the class-room. Third, in the study population students from non-German speaking background are under-represented. Parents’ consent and students’ questionnaire were all written in German. Equally under-represented are students with religious or cultural backgrounds, where research on sexual health is considered inappropriate. Fourth, due to restrictions on the questionnaire design by the senate department for education, science and research in Berlin, we were asked not to enquire on information related to religion and sexual experiences of the students. These factors may play an important role when interpreting the results. Finally, we limited our study to public schools. Results from private schools may be different even though the majority of students in Germany visit public schools.40
Nonetheless, we believe that these results provide important information, and identified barriers should be taken even more seriously when there is a chance of differential non-response.
In conclusion, the observed HPV vaccination coverage was low, and knowledge about HPV and the vaccine was poor, both, in male and female students participating in our study. Besides concerns about vaccine safety, another reason for non-vaccination was that the process of receiving the vaccine is too time-consuming. Schools can be an important resource of informing adolescent students about vaccine related health issues.41
Therefore, with more targeted information on one hand and low-barrier access to vaccination on the other hand, e.g., by offering information and vaccinations at school, HPV-vaccine uptake could be increased. The sole availability of HPV vaccines will not change the burden of cervical cancer in a population, unless there is both widespread demand for and access to those vaccines. Demand requires recognition of the need for protection against HPV infection and knowledge of the fact that HPV vaccines are safe and efficacious. Further efforts are needed to promote the understanding of HPV infection and of the benefits and harms of HPV vaccines among adolescents, family members, and healthcare providers likewise.