Human papillomavirus (HPV)-related neoplasms include cervical, vulvar, vaginal, penile, anal, rectal and oropharyngeal cancer1. More than 80% of HPV-associated cancers affect the cervix, so most of the scientific evidence of vaccines is related to the cervical disease2.
There are currently three prophylactic HPV vaccines. Gardasil®, known as a tetravalent vaccine, which prevents infections from HPV types 6, 11, 16 and 18 and is approved for women aged nine to 45 years and men aged nine to 26 years. Cervarix®, also called bivalent vaccine, is effective against HPV types 16 and 18 and is approved for women aged nine and over, with no upper age bracket3,4. Gardasil 9® vaccine provides coverage for nine HPV types (6, 11, 16, 18, 31, 33, 45, 52, 58), showing potential coverage of approximately 90% of vulvar, vaginal, cervical and anal cancers. It is not currently marketed in Brazil3.
In March 2014, the Unified Health System (SUS) included the tetravalent HPV vaccine in the National Vaccination Program, targeting girls aged 11-13 years. It is currently available for girls aged 9-14 years and boys aged 11-14 years, in two doses with a 6-month interval. It is also available for people living with HIV, transplanted and oncological patients under chemotherapy and radiotherapy, aged 9-26 years, in three doses5.
From the beginning of vaccination until June 2017, 18 million doses were applied to the female population nationwide. In the age group of 9-15 years, in the same period, 10.7 million girls received their first dose, which corresponds to 74.7% of the total Brazilian females in this age group. In total, 7.1 million girls received the full two-dose vaccination schedule recommended by the Ministry of Health, which corresponds to 47% of the target audience. Regarding boys, from January to June 2017, 853,920 adolescents aged 12-13 years received their first dose of the HPV vaccine, which corresponds to 23.6% of the 3.61 million boys in this age group5. Thus, there is a lower vaccine demand than expected with low vaccination coverage.
The major challenge for public health is to develop accurate forms of communication and information about HPV so that people understand the importance of prevention and problems associated with this virus6. To this end, partnerships are being developed with scientific societies and joint work with churches, nongovernmental organizations and the media. The purpose is to clarify that HPV is a public health problem in the country and the importance of vaccination as the most relevant strategy to prevent cervical, vulvar, penile, anal and oropharyngeal cancer.
Accurate knowledge about HPV and its relationship with cervical cancer are critical to make appropriate, evidence-based health care choices. Knowledge levels of students studying at health care-related departments of medical colleges regarding cervical cancer, its risk factors, protection and HPV is important for both, the students and the society in which they will work7,8. Literature students will be future teachers. Teachers' knowledge and attitudes towards the vaccine have been shown to significantly affect the success of HPV vaccination programs. Disseminating the correct information about the vaccine is key in ensuring community support9.
Due to the low vaccine coverage achieved, this study aimed to evaluate the level of knowledge and use of the HPV vaccine among university students.
HPV infection has alarming proportions and is a predisposing factor for several types of cancers, including cervical, vaginal, anal and oropharyngeal cancer. From these data, it is possible to characterize HPV as a public health problem. The infection predominantly affects young, sexually active adults of both genders11.
In Brazil, data from the National Adolescent School-based Health Survey (PeNSE) in 2009, in the Brazilian capitals, showed that, among adolescents aged 14 who have already had sexual intercourse, more than a third had their first sexual intercourse at 12 years old or less. Studies show that early sexual intercourse is associated with unprotected sex and more partners over a lifetime12.
This study was carried out with students of the first and last year of Medicine and Literature courses and the main results showed that most students did not know that vaccination could also be done after sexarch, and female students showed more interest in using the vaccine than male students in both groups (literature and medical students).
The mean age of the students was 23 years in both courses. As expected, most were single and young, up to 24 years of age. The first sexual intercourse occurred on average at the age of 17 among medical students and 18 among literature students, and was earlier in males (p<0.001). These results are in agreement with two large Brazilian studies, the ERICA study with 74,589 Brazilian adolescents who showed the first sexual intercourse in 28.1% of adolescents, with a higher prevalence around 17 years old (56.4%) and in males (33.5%), and the National School Health Survey (PeNSE) conducted in 2012, which showed sexual activity in 28.7% (95% CI 26.4-31.2) of ninth grade students, usually aged 14 to 15 years, including 18.3% (95% CI: 15.3-21.8) of girls and 40.1% (95% CI 26.4-31.2) of boys12,13.
Regarding the use of contraceptive methods, freshmen of both courses reported condom use in 53%, with lower use among the last-year students (27.6% and 36.7%, respectively). Almost half of seniors use combined oral contraceptive pills (COCP). Based on this finding, it can be assumed that because graduating students are older, they are probably in a stable relationship. It is interesting to note that greater knowledge about sexually transmitted infections (STIs) and prevention of these diseases does not imply a greater use of the method, since the COCP is the most used method by M2, while condom is the most used method by M1.
For those who received the vaccine, the study showed that women were vaccinated in larger numbers than men, and that, among literature students, no males used the vaccine. These results are similar to those of Yam et al.14 in Hong Kong, who found adherence to the vaccine of 45.2% of women and 8.8% of men. This can be attributed to the fact that the vaccine development and implementation strategy has been specifically focused on women with the aim of preventing cervical cancer, resulting in vaccine feminization15. In addition, women are the focus of procreative responsibility, thus bearing the burden of contraceptive liability. According to official data, the contraceptive pill is used by 27.4% of Brazilians, with sterilization appearing as the second contraceptive method, adopted by 25.9%. Vasectomy is less frequently reported, by only 5% of males16.
Low vaccine adherence in this study (less than 1/3 of all respondents) can also be explained by the fear of the ensuing risks of vaccination. This was also reported by Yam et al.14 who found that 33.1% of university respondents were concerned about the side effects of the HPV vaccine. A study conducted in Canada analyzing online comments on news sites to understand public perceptions of HPV17 identified several negative comments regarding the composition of the vaccine, the unknown effects and as a cause of chronic diseases, showing a lack of knowledge of the population on the benefits of the vaccine.
Another hypothesis for the low number of vaccinees may be associated with the stigmatic and promiscuous view regarding the use of a vaccine that protects against STIs. Wong and Sam showed that 11.3% of women who did not receive the HPV vaccine reported shame of being vaccinated against STIs18.
Regarding the interest in being vaccinated, this study observed that more female students showed interest in using the vaccine in all groups. In general, students who are starting higher education are more interested in being vaccinated. This may be due to the relatively recent implementation of the HPV vaccine in Brazil, so that students still in the undergraduate years experienced more effectively vaccination campaigns and were aware of the importance of vaccination. In addition, as the focus of the campaign was the female audience, from the moment the government provided the vaccine for free in 2014, it was directed exclusively to women, and it was expected that the public would become more aware of and interested in vaccination19. The low interest of the male public may be partially attributed to the focus mostly given to cervical cancer in the HPV vaccine campaign, so that information such as the prevention of penile, anal, and oropharyngeal cancer had not been highlighted14.
In respect to those who should be vaccinated among Medicine and Literature freshmen, the view that both genders should have access to the vaccine prevailed, in last-year students of both courses most students believed that only women should be vaccinated. Once again, consideration should be given to the recent implementation of the HPV vaccine in Brazil and its vaccine campaign focused on women19. These data are in line with research conducted with students at a university in India20, which has shown that more than half of the students agree that only women should be vaccinated. This fact is worrisome, because men play a significant role in the transmission of the disease, since most of them have more sexual partners than women and, due to their low adherence to the tests, they end up not knowing that they have the disease.
Yam et al.14 observed that medical students, especially those most advanced in the course, had broader knowledge and positive attitudes about HPV vaccination, a behavior attributed to information received during university years, while students from other courses had less access to medical knowledge, and it was reasonable for these students to be less informed about HPV infection and its vaccine. However, when analyzing the vaccination practice in these two groups, there was no significant difference. On the other hand, our data showed that undergraduate students of the two courses have more knowledge about the vaccine than their veterans, while sixth-year medical students have shown a greater technical knowledge about HPV infection, associated pathologies and other aspects. Nonetheless, when analyzing the vaccination rate in these two groups, there was also no significant difference. The higher level of knowledge of students and health professionals about the HPV vaccine can contribute to an increased vaccination coverage, since they begin to have a positive perception, starting to recommend it to their patients. In an open letter to physicians, the Brazilian Society of Immunizations (SBIm), the Brazilian Society of Infectology (SBI), the Brazilian Society of Pediatrics (SBP) and the Brazilian Federation of Gynecology and Obstetrics Associations (FEBRASGO) have warned on how prescription of the HPV vaccine may change the current reality of low vaccine coverage. “Recent studies show that patients receiving recommendation from their doctors are four to five times more likely to get vaccinated. A hesitant, vague or sturdy recommendation may lead the patient to believe that the HPV vaccine is not as important as the others”21. This rationale is confirmed by a study that showed that students with higher levels of knowledge were more motivated to use and recommend vaccination22. A study conducted with medical students and physicians at the Federal University of Parana showed that more than half of the respondents would indicate the vaccine to boys and girls between the ages of 10 and 1523.
As for the vaccination timing, more than 80% of medical students and more than 50% of literature students believe that the HPV vaccine should be given only before the sexarch. When implemented in the National Vaccination Program, the HPV vaccine targeted girls aged 11-13 years, an age range that was increased, and now covers girls aged 9-14 years and boys aged 11-14 years19. This change aims to reach the public before the onset of the sexual life and, consequently, before the contact with the virus. However, the vaccine can be purchased in private clinics for the remaining individuals and is important to protect against HPV types that have not yet been acquired.
It is also possible to understand the importance of vaccination in women diagnosed with HPV to prevent new infections, since the subgroup undergoing prior vaccination evidenced a significant reduction in the incidence of subsequent HPV-related diseases, including severe lesions24.
One of the limitations of this study is that it is a cross-sectional study and the participants represented a convenience sample. After a pilot-testing questionnaire with ten students, we have changed some questions in order to facilitate reading and answering. It was found that dealing with questions directed to sexuality still generates certain discomfort and insecurity, especially for adolescents and young adults. Some participants have questioned, even after signing the Informed Consent Form, about the secrecy of the data and refused to respond after reading the content of the questionnaire. As the research included only students of medicine and literature, we cannot generalize the knowledge regarding HPV-induced diseases and the benefits of vaccination to the general public and to the universe of university students.
Thus, it is evident that, following what is expected in a wider context of dichotomization of vaccine use at a university level, male students are less knowledgeable about HPV vaccination than women, use less the vaccine and show less interest in being vaccinated in all groups interviewed. In addition, vaccination coverage is low among the university population and is higher among medical students. As already mentioned, it may be a result of the recent free implementation of the HPV vaccine in Brazil that did not include a large part of the public interviewed due to the age group, as well as the cost of the vaccine in private clinics. This reflects the difficulty of dealing with HPV as a collective health problem, and it is necessary to rethink its approach in order to achieve more solid and safe immunization rates for the population as a whole.